Molluscan biogeography and biostratigraphy the ...

Molluscan biogeography and biostratigraphy of the Tertiary of southeastern Australia THOMAS A, DARRAGH

DARRAGH,T. A., 1985:03:25. Molluscan biogeography and biostratigraphy of the Tertiary of southeastern Australia. Alcheringa 9, 83-116. ISSN 0311-5518.

A zonation based on Mollusca for the Tertiary of southeastern Australia (Murray, Otway, Bass and Gippsland Basins) is proposed, consisting of a sequence of 18 informal assemblage zones ranging in age from Middle Paleocene to Late Pliocene. The assemblages are defined using the molluscan fauna of a typical locality which gives the name to the assemblage. Factors such as larval dispersal, molluscan distribution, provincial differences, facies variation and the nature of the Tertiary sequence, which affect correlation by means of molluscs, are discussed and have been taken into account when formulating the zones. Composition of the molluscan fauna of the southeastern Australian Province has been analysed under four headings, Australian-New Zealand element, Tethyan IndoPacific element, Endemic element, and Cosmopolitan element. The relative proportions of each element fluctuated with time and it is concluded that the Tethyan Indo-Pacific and Endemic elements increased with time at the expense of the Australian-New Zealand and Cosmopolitan elements. Thomas A. Darragh, Division o f Natural History, Museum o f Victoria, 285 Russell Street, Melbourne, Victoria, Australia, 3000; received22 February 1984.

D U R I N G the 19th a n d early 20th centuries, species o f M o l l u s c a were used as the chief means o f c o r r e l a t i o n o f T e r t i a r y deposits in Australia and, for that matter, throughout the world. W i t h the a d v e n t o f m o r e precise means o f c o r r e l a t i o n using microfossils, their t r a d i t i o n a l role has been s u p p l a n t e d , p a r t i c u l a r l y in i n t e r r e g i o n a l c o r r e l a t i o n . H o w e v e r , a local scheme using molluscs provides a useful s u p p l e m e n t to the microfossil z o n a l schemes, since microfossils m a y either be a b s e n t , r e m o v e d by solution, p o o r l y preserved, or the situation m a y require a r a p i d a n d inexpensive field d e t e r m i n a t i o n w i t h o u t the lengthy p r e p a r a t i o n r e q u i r e d for microfossil d e t e r m i n ation. O v e r 1,600 species o f M o l l u s c a have been described f r o m the T e r t i a r y o f A u s t r a l i a ( D a r r a g h , 1970) a n d there are several h u n d r e d m o r e u n d e s c r i b e d species. F r o m this large n u m b e r , c e r t a i n taxa have been chosen w h o s e s t r a t i g r a p h i c ranges, particularly their first a p p e a r a n c e in the s t r a t i g r a p h i c c o l u m n , a r e k n o w n with s o m e degree o f c o n f i d e n c e a n d with this inf o r m a t i o n 18 i n f o r m a l a s s e m b l a g e zones recognised f o r the M i d d l e P a l e o c e n e to Pliocene s t r a t a o f the M u r r a y , O t w a y , Bass, a n d G i p p s l a n d Basins (Fig. 1). T h e base o f each a s s e m b l a g e is d e f i n e d by first a p 0311/5518/85/010083-34 $3.00 ©AAP

p e a r a n c e o f key taxa a n d the t o p o f each a s s e m b l a g e is d e f i n e d by the base o f the succeeding a s s e m b l a g e . A s s e m b l a g e s have not been n a m e d f o r a p a r t i c u l a r taxon, since f u t u r e w o r k m a y refine the scheme. A l s o , the a s s e m b l a g e s a r e n o t a s s e m b l a g e zones in the strict sense, as they are also based o n a typical locality. In this respect they resemble b o t h the m a m m a l i a n ' f a u n a s ' set up b y Stirton, T e d f o r d & Miller (1961) for Australian Tertiary rocks of continental

CA

BASIN ~ BASSBASIN

~GIPPSLANO BASIN

Fig. 1. Distribution of Tertiary sedimentary basins in Australia (after Brown et al., 1968).

84

T.A. DARRAGH

origin and the New Zealand marine Tertiary stages of Finlay & Marwick (1940). The latter authors defined the type localities and listed characteristic fossils of each stage based on restricted forms and first and last appearances. Blackwelder (1981) nominated zones for the Late Cainozoic of the United States Atlantic coastal plain using similar methods.

Previous work The first serious attempts at correlation of the Australian Tertiary were based on the gross appearance of the molluscan assemblages, which were compared with those of the European Tertiary (McCoy, 1861, 1867). Localities with similar suites of molluscs were grouped together, though few species were described at that time and stratigraphical control of the sequence of faunas was lacking. When a large number of molluscs had been described, subdivision was based on the Lyellian method of the percentage of living species defining a particular horizon (Tate & Dennant, 1893; Hall & Pritchard, 1896). Since few living species were recognised in the fossil record, the Lyellian method placed most of the localities in the Eocene or Miocene, ages much older than those subsequently determined by other methods. To overcome some of the confusion arising from application of the Lyellian method and differences in opinion on stratigraphic succession, Hall & Pritchard (1902) erected a series of local stage names for the subdivisions of the Tertiary of Australia and based each on a distinctive macrofauna cited from a type locality. Correlation was by comparison of gross suites of described molluscs. The stages remained in use with little alteration until 1941 when F. A. Singleton redefined the stages on lithostratigraphical grounds, in contrast to Hall & Pritchard's (1902) essentially biological concept, and listed species which he regarded as characteristic of each stage. Singleton's paper was the last in which Mollusca were used almost exclusively for the subdivision of the Australian Tertiary, as two years later Crespin (1943) zoned the Tertiary o f Gippsland using lithostratigraphic methods and Foraminifera, and erected three new stages based on this group of microfossils. Each stage o f the Tertiary

ALCHERINGA

also had a zonal macrofossil allotted to it (Crespin, 1943, table 1), but the significance of these was not discussed. The zonal macrofossils seem to be the most common macrofossils occurring in the particular stage irrespective o f their time ranges. Later schemes o f zonation based on pelagic foraminifera have been discussed by Abele et al. (1976) and Mallett (1977). In 1967, O. P. Singleton (1968, table 1) provided a sequence of ages of macrofossils to match the foraminiferal zones, but the details of the scheme were not published. The only published application of this scheme is that of Darragh (1969, table 1) who grouped together localities and indicated ranges in terms of O. P. Singleton's scheme. Ludbrook (1973) discussed, in broad terms, the Tertiary stratigraphy of southern Australia, placed the classical localities from which Mollusca have been described into a modern biostratigraphic framework based on microfossils, and provided lists of species and illustrations of some of the characteristic molluscan taxa from each stage.

Problems of correlation Reliable correlation requires a wide distribution of the fossils used and, unfortunately, there are a number of limitations on the distribution of many fossil molluscs. Factors which affect the distribution are larval dispersal, substrate, currents and water temperatures and depths. Some of these factors are interdependent and all interact to affect the distribution of a particular species. Geological factors, such as the limitation of outcrop, which affect the collecting of macrofossils are self-evident and are not discussed; however, the nature of the Tertiary sequence is important and a brief account of its stratigraphy and molluscan content is given below. Since the majority of Tertiary molluscs are crawling or burrowing benthonic animals as adults, the distribution of a given species will be dependent to a large extent on the nature of the larval stage. Those species with a long pelagic larval stage, such as many cymatiids, cypraeids and strombids, will tend to have a wider distribution than those species with direct development of crawling juveniles from the eggs such as most volutes (Wilson, 1971; Scheltema, 1971 and references therein).

MOLLUSCAN BIOGEOGRAPHY

ALCHERINGA

Valentine (1961, 1967) has discussed the effect of water temperature on marine molluscs and concluded that temperature is probably the chief factor in controlling their geographic range. Differences in water temperature are among the main controlling factors in the development of marine faunal provinces which are discussed in more detail below. Type of substrate and depth of water are also important limiting factors. For example part of the molluscan fauna of the Early to Middle Miocene silty sediments (Gellibrand and Fyansford Formations) is closely related to that presently found in the deeper waters of the continental shelf (Hedley, 1902). Species of such genera as Xenophora,

Notopeplum, Notovoluta, Columbarium, Austroharpa, Nucula and Verticordia, which are found in such waters and Miocene silty sediments, are not found in shallow water sandy sediments of southeastern Australian Pliocene. On other hand, species o f such genera

in the the the as

Placamen, Bassina, Leiopyrga, Bankivia, Sydaphera and Tylospira, which are

common at present in shallow waters on a sandy substrate, are also common in shallow water sediments of the Pliocene and Pleistocene, but are rare or absent in older sediments of deeper water origin. Rock dwellers, such as Dicathais and Haliotis, though known, are generally rare in the Tertiary, since the faunas of rocky environments are rarely preserved. The rather meagre macrofossils of the Tertiary calcarenites usually have little in common with those of arenaceous or argillaceous sediments, reflecting the different ecological requirements of the fossils found therein. Facies variations, therefore, limit the distributions of molluscs both in space and time, thus lessening their value for correlation purposes. In this paper, the faunas of the argillaceous and arenaceous sediments have been used, since such sediments comprise the bulk of the fossil record in Victoria. A complementary scheme for the bryozoal calcarenites, based on a group such as the Pectinidae and tied in with the present scheme, is a major work in itself and has not been attempted here.

Provinces Because of limits on the distribution of molluscs and other macrofossils, areas can

85

be mapped on the globe which have a common fauna with a large endemic element. These areas, or faunal provinces, are not stable with time, but evolve with the changes which occur in the distribution of land and sea (Sylvester-Bradley, 1971). The existence of Tertiary faunal provinces proves to be an important factor in the value of correlation by means of molluscs and, depending on the degree of endemism present, will limit reliable correlation to regions within the province. That this is the case in southern Australia is shown below. The Australian coastline has been subdivided into six provinces (Bennett & Pope, 1953) based on the alleged high number of endemic species present in each province as defined. However, most of the species cited by these authors are intertidal and at moderate depths the endemic element of the particular area is much lower. Wilson (1971, p. 18) states that 'our knowledge of the Australian marine fauna is, as yet, very imprecise. Consequently, views on the number and limits of faunal provinces vary, often depending on the group of animals in which the taxonomist specialises'. No doubt many of the alleged endemic taxa are the result of excessive taxonomic 'splitting' in the past and future work will reduce the endemic element in each of the provinces. However, notwithstanding the above comments, Wilson (1971), as Ekman (1953) had done previously, drew attention to the fact that the Australian coast can be readily divided into two regions based on the distribution of molluscan species (Fig. 2). These are the Northern Australian Region, which is part of the tropical Indo-West Pacific faunal province, and the Southern Australian Region, which has a unique temperate marine mollusc fauna, having little in common with other regions. This has been confirmed and elaborated upon by Wells (1980). The molluscan fauna of the Southern Australian Region has, for the most part, its origin in the fauna of the southeastern Australian Tertiary. This latter fauna, part of which was established by the Late Eocene, is composed of several elements whose proportions in the fauna fluctuated with time. These elements are 1. Neo-Zelandic, 2. Tethyan Indo-Pacific, 3. Endemic and 4. Cosmopolitan and are set out and analysed in detail below. The Tethyan Indo-Pacific element was strongest during the Early to Middle

86

T.A. D A R R A G H

ALCHERINGA

boundaries of which are delimited by climatic factors, as are the boundaries of most marine faunal provinces (Valentine, 1961, 1967). These are the Austral IndoPacific Province and the Southeast Australian Province (Figs 3-4).

NT

A ustral lndo-Pacific Province OLD WESTERN OVERLAP

ZONE

W.A

--

. . . . . . . .

~

EASTERN

OVERlAp

Fig. 2. Major faunal regions on the Australian coast (after Wilson, 1971).

Miocene, which implies an increase in sea water temperatures during that time in order that migration from the north could occur. However, the Early to Middle Miocene of the southeast could scarcely be called tropical as some authors have suggested (Knox, 1980 and references therein). Despite the larger Indo-Pacific element in the southeast during the Middle Tertiary, the Indo-Pacific element in the Early Miocene to Pleistocene was much stronger in the Eucla and St Vincent Basins and includes genera, e.g. Anodonta, Veremolpa, which are lacking in the southeast. This implies even warmer water temperatures than those in the southeast; so much so, that Ludbrook (1954) has suggested that the fauna of the Pliocene Dry Creek Sands is tropical. Indo-Pacific immigrants to the southeast were filtered by some form of barrier east of Kangaroo Island and by a barrier on the east coast of Australia. This barrier seems most likely to have been a change in temperature, possibly due to the presence of relatively cool currents from the south, which in effect 'define' the study area. Chaproniere (1980) has also concluded that ocean currents had a marked effect on the southern extension of the range of tropical larger foraminiferids during the Early to Middle Miocene and regarded the southeast Australian Region as marginal to the tropical region. One can then define on the basis of their faunas, two provinces in the Middle Tertiary of the Southern Australian Region, the

This province was an extension of the IndoPacific Province along the west and south coasts of Australia into the Eucla and St Vincent Basins. It was first defined by Crespin (1950) on the basis of a particular assemblage of subtropical larger Foraminifera which was not present in southeastern Australia in the Middle Tertiary, but was present in the Indonesian Tertiary. Ludbrook (1954, 1969) has since confirmed Crespin's work on the basis of the distribution of molluscs and estimated water temperatures for the Early Miocene to be 'in the vicinity of 23 °-25 ° '. In southern Australia, this province includes the St Vincent and Eucla Basins and is characterised by the Diastoma-CampanileAnodontia-Miltha assemblage which Ludbrook (1971) has shown extends from the Early Miocene to the Early Pleistocene in these basins. The development of this province in the Early Miocene is based on the following evidence: 1. The faunas of the Late Eocene Pallinup Formation, Blanche Point Marl and Browns Creek Clay are similar and exhibit very

? 13 BASIN

6

~

BASIN

BASS B A S I N

Fig. 3. Southern Australian Tertiary marine basins and the marine faunal provinces to which they are assigned. Late Eocene to Early Miocene.


ALCHERINGA

G

•

~t 4

D BASIN

@~i)i!!i Southeast Australian Province.

Fig. 4. Southern Australian Tertiary marine basins and the marine faunal provinces to which they are assigned. Late Early Miocene to Pleistocene.

minor regional differences. (See faunal lists herein - - Table 1). 2. Molluscan faunal lists by Ludbrook in Lowry (1970) show that the Late Eocene Wilson Bluff Limestone and the Early Miocene (Longfordian) Abrakurrie Limestone both of the Eucla Basin have faunas similar to sediments of those ages in the Murray and Otway Basins. There is no undoubted Oligocene record (Lowry, 1970). 3. In contrast, the late Early to Middle Miocene Nullarbor Limestone of the Eucla Basin (Lowry, 1970) has many Indo-Pacific foraminifera and some mollusca not present in southeastern Australia (Ludbrook, 1958; Ludbrook in Lowry, 1970). The Melton Limestone of the St Vincent Basin also has a fauna of foraminifera (Lindsay, 1970) and molluscs (Ludbrook, 1971) similar to that of the Nullarbor Limestone. The persistence of this Province into the Pliocene and Early Pleistocene is well documented by Ludbrook (1954, 1978 and references therein) and her work on the molluscan faunas of the Late Pliocene Dry Creek Sands and Early Pleistocene Roe Calcarenite are the only comprehensive accounts of faunas in this province. Ludbrook effectively demonstrated that the tropical Indo-Pacific element was prominent in this fauna, which is in marked contrast to the situation in the Victorian Pliocene and Pleistocene. Correlation between the Victorian and South Australian Pliocene is

87

therefore difficult, since the faunas of the two areas have so little in common. During the Pliocene some of the Tethyan Indo-Pacific genera characteristic of the province penetrated into the Western Murray Basin as shown by the presence of Diastoma and Anodontia in the Pliocene of Moorlands (Ludbrook, 1959); however, this area is close to the province boundary and there is bound to be some overlap. These genera have not been recorded from older strata in the Murray Basin and have not been found further east in Victoria. By Early Pleistocene time at the latest it seems that the Austral Indo-Pacific Province was reduced to the area of the Eucla Basin, since the Roe Calcarenite (Lowry, 1970) has the characteristic Diastoma-CampanileAnodontia-Miltha assemblage (Ludbrook, 1971, 1978) but further westward in the Perth Basin, Kendrick has asserted that the Plio-Pleistocene molluscan fauna there has strong affinities with the molluscan faunas in southeastern Australia (Darragh & Kendrick, 1971). Ludbrook (1969) points out that the restriction of the range of the genus Miltha in the Pleistocene could be explained in terms of higher Pleistocene sea temperatures in the Bight, analogous with lower sea temperatures in Bass Strait at the present day. Presumably a similar latitudinal temperature variation existed during the early Pleistocene, but the temperatures would have been slightly higher than at present since Miltha is now extinct in Australia. At the present day the western half of the southern coast of Australia is included in the temperate Southern Australian Region, as the fauna, at least at the generic level, is similar to that of the eastern half; however, a few relics of the Austral Indo-Pacific fauna, such as Campanile and Diastoma, still remain, presumably adapted to cooler water conditions.

Southeastern Australian Province The Southeastern Australian Province is introduced to replace the name of the province originally defined by Crespin (1950) as the Bass Strait Province, but not used for the reason, cited by Ludbrook (1954), that there is already a Bassian Faunal Province widely used by biogeographers for the terrestrial fauna of Tasmania. It will be seen from the previous discussion that the area of this Province has varied with time. In Late Eocene to Early Miocene time the

88

T.A. DARRAGH

Eucla, St Vincent, Murray, Otway, Bass and Gippsland Basins were included in this Province, since their faunas were similar. However, in late Early Miocene to Early Pleistocene time only the Gippsland, Bass, Otway and Murray Basins are included, the Eucla and St Vincent Basins constituting part of a newly formed Austral Indo-Pacific Province. The fauna of the present temperate Southern Australian Region is largely derived from the fauna of the Southeastern Australian Province as mentioned above. This paper is concerned only with the latter and the assemblages proposed by the writer below can only be used reliably within it.

ALCHERINGA

180

Analysis of the fauna of the Southeastern Australian Province

As mentioned earlier, it is proposed to discuss the broad composition of the fauna of this Province in terms of the faunal elements previously listed. The analysis is similar to that done by Fleming (1967) for the New Zealand Tertiary using much the same criteria. The genera have been taken from Darragh (1970) with some modification from later work and they have been classified according to their distributions as given in Wenz (1938-1944) and the 'Treatise', but modified if considered to be erroneous. A total of 297 genera have been listed which are thought to be identified reliably. Many genera have been omitted from the analysis, as their identity and occurrence in the fauna is in doubt. Therefore, this analysis should be regarded as tentative, but it is hoped that genera listed cover a representative proportion of the whole fauna. Such analysis is highly subjective, particularly in two areas, the taxonomic decision of an author in accepting a taxon and the placement of that taxon into a particular biogeographic category as Fleming (1967) has noted. In plotting time ranges, the occurrence of a particular taxon is based on material held in the collections of the National Museum of Victoria. The total number of genera of each biogeographical element occurring within a particular time interval has been graphed, and also those figures have been converted to a percentage of the total fauna corresponding to the particular time and graphs produced. The fauna of the Early

120

100

80

Fig. 5. Faunal analysis. Totalnumberof generaused.

Oligocene is limited owing to paucity of outcrop, and the figures for this portion of the stratigraphic column are probably not as reliable as those for others. Australian-New Zealand element

This is composed of those genera common to Australia and New Zealand and not known to occur outside these regions. Fleming (1967) uses the term Australian in his analysis of the New Zealand fauna for this element. No attempt has been made to determine whether a particular genus originated in New Zealand and migrated to Australia, or vice versa. Both the New Zealand and Australian Endemic Elements probably have their origin in the southerncircum Pacific Paleoaustral Fauna (Fleming, 1979; Zinsmeister, 1982).


ALCHERINGA

89

I I 3o___f-q__ 1

I

I.

i A

I wlwrll l J

~o ~~_~ ~

~o

B

0: o

~

oo oo

~o

~o

we, ~-o

m

Fig. 6. Australian-New Zealand Element. A, total number of genera used. B, percentage of total fauna.

T h e p r o p o r t i o n o f this element in the e x a m i n e d f a u n a is a b o u t 26% o f the L a t e Eocene, 30°7o in the E a r l y Oligocene, then falling to 17% in the P l i o c e n e a n d Pleistocene. T h e m a x i m u m n u m b e r o f genera (49) occurs in the M i d d l e M i o c e n e (Fig. 6). Time ranges o f genera. Poroleda (Lt. Eoc. - - Rec.), Notogrammatodon (Lt. Eoc. - M. Mioc.), Cosa (Lt. Eoc. - - M. Mioc.), Serripecten (Lt. Olig. - - Lt. Mioc.), Notostrea (Lt. Eoc. -E. Olig.), Eucrassatella (E. M i o c . - - Rec.), Spissatella (Lt. Olig.), Hedecardium (Lt. Eoc. - - M. Mioc.), Dosina (Lt. E o c . - - E. Mioc.), Hina (Lt. Eoc. - - M. M i o c . ) , Fossacallista (Lt. Eoc. - - Rec.), Kereia (Lt. Olig. - - Rec.), Tawera (Lt. Olig. - - Rec.), Callanaitis (Lt. Olig. - - Rec.), Cleidothaerus (E. Mioc. - Rec.), Montfortula (E. Mioc. - - Rec.), Actinoleuca (M. M i o c . - - Rec.), Cantharidus (E. M i o c . - - Rec.), Astraea (E. Olig. - - Lt. M i o c . ) , Spectamen (E. Mioc. - Rec.), Pareora (Lt. Eoc. - - E. Olig.), Spirocolpus (Lt. Eoc. - - Lt. Olig.), Maoricolpus (E. Mioc. -Rec.), Discotectonica (E. - - M. Mioc.), Notacirsa

(Lt. Eoc. - - E. Olig.), Clypeola (Lt. Eoc. - Rec.), Calyptropsis (Lt. Eoc. - - M. Mioc.), Zeacrypta (E. Mioc. - - Rec.), Archierato (Lt. Eoc. - - M . M i o c . ) , Proterato (Lt. Eoc. M. M i o c . ) , Ellatrivia (Lt. Eoc. - - Rec.), Willungia (Lt. Eoc. - - Lt. M i o c . ) , Friginatica (Lt. Eoc. - - Rec.), Tanea (Lt. Eoc. - - Rec.), Taniella (Lt. Olig. - - M . Mioc.), Proxiuber (M. Mioc. - - Rec.), Cymatiella (M. Mioc. - - Rec.), Antizafra (M. Mioc. - - Rec.), Brocchitas (M. M i o c . ) , Penion (Lt. Olig. - - Rec.), Alocospira (Lt. Mioc. - - Rec.), Gracilispira (Lt. Eoc. - - M. Mioc.), Lamprodomina (M. Mioc.), Eumitra (M. Mioc. - - Rec.), Parvimitra (M. Mioc.), Peculator (E. Plio.), Waimatea (Lt. Eoc. - - M. M i o c . ) , Waihaoia (Lt. Eoc. - M. Mioc.), Alcithoe (Lt. Mioc., Lt. Plio.), Inglisella (Lt. E o c . - - M . Mioc.), Anapepta (Lt. Eoc. - - M. M i o c . ) , Oamaruia (Lt. E o c . Rec.), Semitriton (Lt. Eoc. - - E. Olig.), Marshallaria (E. Olig.), Austrotoma (Lt. Olig. - - E. M i o c . ) , Scrinium (Lt. Olig. - Rec.), Mitrithara (M. M i o c . ) , Vexithara (Lt. Eoc.), Maoritomella (Lt. Olig. - - Rec.), Hautura (M. M i o c . ) , Austroclavus (M. Mioc.), Antiguraleus (Lt. Olig. - - Rec.), -

-

-

-

90

T.A. DARRAGH

ALCHERINGA

u-

r 30

20

7

I

---,I A

B

10

u~m

°_o tuo

-~u

oo

tu~

j',,) ~0

wu

we.

Je-

a:

.IeHHgggHgi

Fig. 7. Tethyan Indo-Pacific Element. A, total number of genera used. B, percentage of total fauna.

Etremopsis (M. Mioc.), Rugobela (Lt. Eoc. - - Lt. Olig.), Zemacies (Lt. Olig.). Tethyan lndo-Pacific element This element represents the northern or tropical influence in the fauna and consists of taxa, either now or in the past, having their major distribution in the tropical IndoPacific Realm, or parts of it, and which had their probable origin in the Indo-Pacific Basin; as well as those taxa which had their major distribution in the Early Tertiary through the Palaeogene Tethyan area of the Mediterranean region east to Indonesia and west to the Caribbean region. This element

forms the major part of the living fauna of tropical northern Australia and was probably present in northern Australia throughout the greater part of the Tertiary, if the Neogene faunas of New Guinea and Indonesia can be taken as a guide. This concept is essentially the Indo-Pacific Element of Fleming (1967), though some of the genera included in it by him are regarded as having a cosmopolitan distribution and are included in the Cosmopolitan Element. It partly includes both the Recent IndoPacific and Tethyan Eocene Elements of Ludbrook (1954).


ALCHERINGA

A plot of the n u m b e r of Indo-Pacific genera present against time produces a histogram s o m e w h a t similar to those d r a w n by Fleming (1967, fig. 4) and Beu & Maxwell (1968, fig. 1) for New Zealand, but with the notable difference that the peak of the Australian g r a p h is located in the Middle Miocene, in contrast to the Early Miocene in New Zealand. In the compilation of the graph, the terms Early and Middle Miocene are used in much the same sense as in New Zealand (using foraminiferal zones) so that this is not an artifact of differing terminology. The p r o p o r t i o n of I ndo-Pacific genera in the examined f a u n a is 25°70 in the Late Eocene, 2307o in the Early Oligocene, rising to 33°7o in the Mid Miocene and remaining fairly constant in p r o p o r t i o n (30070) through the Pliocene and Pleistocene. The m a x i m u m n u m b e r of genera present is 72 in the Middle Miocene c o m p a r e d with Fleming's figure of 100 genera in the Early Miocene o f New Zealand. As noted above, the writer did not include some c o s m o p o l i t a n genera, such as

Glycymeris, A rcopsis, A rca, A trina, Isognomon, Spondylus, Plicatula and Cardita in the Indo-Pacific element as

Fleming has done. So the figures may be more c o m p a r a b l e if such genera were included. Beu & Maxwell (1968) have produced a graph of the percentage of IndoPacific molluscan genera in the total recorded molluscan fauna of New Zealand, which, unlike the southeastern Australian graph, has two peaks, one in the Late Eocene and the other in the Early Miocene. Also there is b o t h an absolute and a relative decline in p r o p o r t i o n through to the end of the Tertiary (Fig. 7). These differences can be attributed, perhaps, to ocean current patterns, as C h a p r o n i e r e (1980) has suggested to explain differences in the distribution o f w a r m water larger foraminifera between New Zealand and southern Australia.

Time ranges of genera. Sarepta (Lt. Eoc. - Hormomya (Lt. Olig. - - Rec.), Trichomya (E. Plio. - - Rec.), Solamen (Lt. Olig. - - Rec.), Streptopinna (E. Mioc.), Pinctada (Lt. Plio. - - Rec.), Lentipecten (E. Mioc.), Pododesmus (E. Mioc. - - E. Plio.), Epicodakia (M. Mioc. - - Rec.), Codakia (Lt. Mioc.), Miltha (Lt. Mioc. - - Lt. Plio.), Chama (Lt. Eoc. - - M. Mioc.), Vimentum (Lt. Mioc. - - R e c . ) , Arcturellina (Lt. Mioc. - - E. Plio.), Pleuromeris (E. Plio.), Condylocardia (Lt. Mioc. - - Rec.), Crassatella Rec.),

91

(E. - - M. Mioc.), Pratulum (Lt. Eoc. - Rec.), Hemidonax (Lt. Olig. - - Rec.), Semelangulus (Lt. Eoc., Rec.), Strigilla (E. Plio.), Semele (E. Plio. - - Rec.), Solecurtus (Lt. Olig - - M. Mioc.), Sunetta (E. Plio. - Rec.), Katelysia (M. Mioc. - - Rec.), Venerupis (E. Plio. - - Rec.), Placamen (Lt. Mioc. - - Rec.), Panopea (Lt. Olig. - - Rec.), Pholas (E. Plio. - - Rec.), Myadora (Lt. Eoc. Rec.), Clavagella (Lt. Eoc. - - Rec.), Perotrochus (E. Mioc.), Emarginula (Lt. Olig. - - Rec.), Scutus (E. Mioc., Rec.), Tugali (E. Mioc. - - Rec.), Scutellastra (E. Plio. - - Rec.), Cellana (Lt. Eoc. - - Rec.), Cocculinella (M. Mioc. - - Rec.), Basilissa (Lt. Eoc. - - Rec.), Thalotia (E. Mioc. - Rec.), Bolma (Lt. Eoc. - - E. Mioc.), Liotina (Lt. Eoc. - - M. Mioc.), Collonista (Lt. Eoc. - - M. Mioc.), Crossea (Lt. Eoc. - - Rec.), Phasianella (Lt. Mioc. - - Rec.), Amphinerira (Lt. Mioc. - - Rec.), Chavanicerithium (E. - - M. Mioc.), Colina (M. Mioc.),Ataxocerithium (Lt. Eoc. - - Rec.), Orthochetus (Lt. Eoc.), Margineulima (Lt. Eoc. - - Rec.), Niso (Lt. Eoc. - - Lt. Mioc.), Calyptraea (Lt. Olig. - - M. Mioc.), Xenophora (Lt. Olig. - Rec.), Zoila (Lt. Olig. - - M. Mioc.), Notadusta (M. Mioc.), Cypraedia (Lt. Eoc.), Amphiperas (M. Mioc.), Pellasimnia (M. Mioc.), Ampullina (Lt. Eoc.), Sigaretotrema (M. Mioc. -Rec.), Cassidaria (Lt. Olig. - - M. Mioc.), Ranella (M. Mioc.), Sassia (= Austrosassia) (Lt. Eoc. - - Rec.), Biplex (E. - - M. Mioc.), Personella (Lt. Olig.), Eudolium (M. Mioc.), Ficus (E. Mioc.), Columbarium (Pal. - - Rec.), Chicoreus (Lt. Eoc. - - Lt. Mioc.), Typhis (Lt. Olig. - - Rec.), Cyphonochelus (M. Mioc. - - Rec.), Typhina (M. Mioc.), Concholepas (M. Mioc.), Conomitra (M. Mioc.), Tudicla (M. - - Lt. Mioc.), Eocithara (M. Mioc.), Baryspira (Lt. Olig. - - M. Mioc.), Dibaphimitra (M. Mioc.), Costellaria (M. Mioc. - - E. Plio.), Lyria (Lt. Olig. - - Rec.), Leptoscapha (M. Mioc.), Cymbiola (Lt. Olig. - - Lt. Plio.), Scalptia (E. - - M. Mioc.), Unitas (E. - - M. Mioc.), Comitas (Lt. Eoc. - - M. Mioc.), Apiotoma (Lt. Eoc. - - M. Mioc.), Cochlespira (Lt. Eoc. - - M. Mioc.), Lucerapex (M. Mioc.), Turris (M. Mioc.), EpMirona (M. Mioc. - - Rec.), Borsonia (Lt. Eoc. - - E. Mioc.), Micantapex (Lt. Olig. - Rec.), Inquisitor (M. Mioc. - - Rec.), Tomopleura (M. Mioc.), Microdrillia (M. Mioc.), Splendrillia (M. Mioc. - - Rec.), Conorbis (Lt. Eoc. - - E. Olig.), Etrema (Lt. Olig. - - Rec.), Heterocithara (M. Mioc. - -

-

92

T.A. D A R R A G H

ALCHERINGA

Rec.), Daphnella (M. Mioc. - - Rec.), Asperdaphne (M. M i o c . - - Rec.).

Southern A ustralian Endemic element A s the n a m e implies, the genera c o m p r i s i n g this g r o u p have not yet been f o u n d outside the S o u t h e r n A u s t r a l i a n R e g i o n (Fig. 2). T h e p r o p o r t i o n of this element consists of a b o u t 2 4 % o f the whole f a u n a in the L a t e Eocene, rising steadily with time to 34°-/o in the P l i o c e n e a n d Pleistocene. A b s o l u t e numbers o f g e n e r a are 25 in the L a t e Eocene, 63 in the M i d d l e M i o c e n e a n d 55 in the Pliocene a n d P l e i s t o c e n e (Fig. 8).

Time ranges o f genera. Propeleda (M. Mioc. Rec.), Scaeoleda (Lt. Olig. - - Rec.), Melaxinea (Lt. Plio. - - Rec.), Limarca (Lt. Eoc. - - E. Olig.), Exosiperna (Lt. Eoc. - Rec.), Equichlamys (Lt. Plio. - - Rec.), -

-

Mesopeplum (Lt. Olig. - - Rec.), Eotrigonia (M. Pal. - - Lt. Mioc.), Neotrigonia (M. Mioc. - - Rec.), Salaputium (Lt. Eoc. - Rec.), Zenatiopsis (E. Mioc. - - E. Pleist.), Zenatina (E. Plio. - - Rec.), Plebidonax (Lt. Mioc. - - Rec.), Proxichione (Lt. Olig. - Rec.), Capistrocardia (M. Mioc.), Myochama (Lt. Olig. -Rec.), Phragmorisma (Lt. Olig. -Rec.), Marinauris (E. Mioc. - - Rec.), Notohaliotis (E. Mioc. - - Rec.), Cosmetalepas (Lt. Eoc. Rec.), Bankivia (Lt. Mioc. - - Rec.), Herpetopoma (Lt. Eoc. - - Rec.), Leiopyrga (Lt. Mioc. - - Rec.), Laet~fautor (M. Mioc. - - Rec.), Euninella (Lt. Olig. - - Rec.), Subninella (E. Plio. - - Rec.), Jetwoodsia (Lt. Eoc. - - M. M i o c . ) , Sirius (Lt. Eoc. - - Rec.), Tylospira (Lt. Mioc. - - Rec.), Semitrivia (M. Mioc.), Nototrivia (M. Mioc.), Gigantocypraea (kt. Olig. - - M. Mioc.), -

-

I

I

I I

"

I

--I

A

B

too

Fig. 8. Endemic Element. A, total number of genera used. B, percentage of total fauna.


ALCHERINGA

Austrocypraea (Lt. Olig. -Rec.), Notoluponia (M. M i o c . ) , Notocypraea (E. Plio. - - Rec.), Umbilia (Lt. Olig. - - Rec.), Rhynchocypraea (Lt. Olig. - - M. Mioc.), Palliocypraea (E. - - M. Mioc.), Conuber (Lt. Olig. - - Rec.), Austrocochlis (E. Mioc. - - M. Mioc.), Antephafium (Lt. Eoc. - Rec.), Hypocassis (M. Mioc. - - Rec.), Obex (M. Mioc. - - Rec.), Ratifusus (Lt. Eoc. - Rec.), Austrotriton (E. Mioc. - - Rec.), Serratifusus (E. - - M. Mioc.), Hispidofusus (E. - - M. Mioc.), Xenotrophon (M. Mioc. - - Rec.), Enatimene (Lt. Eoc. - - Rec.), Bedeva (Lt. Mioc. - - Rec.), Retizafra (E. Mioc. - - Rec.), Pseudovaricia (M. Mioc.), Dennantia (Lt. Eoc. -E. Plio.), Austrolithes (Lt. Eoc. - - M. Mioc.), Solutofusus (E. - - M. Mioc.), Tectifusus (Lt. Eoc.), Zemira (E. Olig. - - Rec.), Gemmoliva (Lt. Eoc. - - Rec.), Ancillista (Lt. Eoc. - - Rec.), Cupidoliva ( k t . Mioc. - Rec.), AItivasum (E. Mioc. - - Rec.), Austroharpa (Lt. Olig. - - Rec.), Ternivoluta (E. Olig. - - Rec.), Livonia (Lt. Olig. - Rec.), Ericusa (Lt. Olig. - - Rec.), Amoria (M. Mioc. - - Rec.), Nannamoria (Lt. Olig. - - Rec.), Notovoluta (Lt. Eoc. - - Rec.), Notopeplum (Lt. Eoc. - - Rec.), Sydaphera (Lt. Olig. - - Rec.), Paramarshallena (L. Eoc.), Belophos (E. Mioc.), Belatomina (E. -M. Mioc.), Johannaia (L. Eoc.), Liratomina (Lt. Olig. - - M. Mioc.),

30

Epidirella (E. Plio. - - Rec.), Cryptocordieria (L. E o c . ) , Cinguliturris (E. M. Mioc.), Cryptoborsonia (Lt. Olig. - - M. Mioc.), Guraleus (L. Eoc. - - Rec.), Filodrillia (M. Mioc. - - Rec.), Teleochilus (Lt. Eoc. - - Rec.), Syngenochelus (Lt. Eoc. - - Lt. Olig.), Parasyngenochilus (Lt. Eoc. -

--

Cosmopolitan element These genera have a wide d i s t r i b u t i o n t h r o u g h o u t the world, b o t h in space a n d time. In the L a t e Eocene, they c o m p r i s e a b o u t 25% o f the f a u n a , d r o p to 15% in the Mid M i o c e n e a n d rise to 19% in the P l i o c e n e a n d Pleistocene. A b s o l u t e numbers are, however, fairly u n i f o r m t h r o u g h the T e r tiary at a b o u t 28 (22-33) (Fig. 9). This is to be expected in such a g r o u p , the m e m b e r s o f which are t o l e r a n t o f a wide range of conditions a n d have g o o d dispersal capacities.

Time ranges of genera. Ennucula (Lt. Eoc. - - Rec.), Nuculana (Pal.), Ledella (Lt. Eoc. - - M. Mioc.), Saccella (Lt. Eoc. - - M. Mioc.), Arca (Lt. Eoc. - - Rec.), Barbatia (Lt. Eoc. - - Rec.), Cucullaearca (Lt. E o c . ) , Cucullaea (Pal. - - Lt. Plio.), Arcopsis (Lt. Eoc.), Limopsis (Pal. - - Rec.), Glycymeris (Lt. Eoc. - - Rec.), Mytilus (E. Plio. - Rec.), Brachidontes (E. Plio. - - Rec.), Ryenella (Lt. Eoc. - - Rec.), Modiolus (Lt.

I

!

,

A

LId~

~_~

~o

I

B

..o ~o

~

-

E. Olig.).

ill'

IF

93

~,

Fig. 9. Cosmopolitan Element. A, total number of genera used. B, percentage of total fauna.

94

T.A. DARRAGH

Eoc. - - Rec.), A trina (Lt. Olig. - - Rec.), Pteria (Lt. Eoc.), Isognomon (E. Plioc.), Vulsella (Lt. Eoc.), Propeamussium (Lt. Eoc. - - M. Mioc.), Chlamys (L. Eoc. - Rec.), Pecten (E. Pleist. - - Rec.), Plicatula (E. - - M. Mioc.), Spondylus (Lt. Eoc. - Rec.), Dimya (Lt. Eoc. - - Rec.), Lima (Lt. Eoc. - - Rec.), Limaria (Lt. Eoc. - - Rec.), Limatula (Lt. Eoc. - - Rec.), Limea (Lt. Eoc. - - Rec.), Ostrea (Lt. Eoc. - - Rec.), Diplodonta (Lt. Olig. - - Rec.), Cardita (Lt. Eoc. - - Rec.), Mactra (M. Mioc. - - Rec.), Solen (E. Plioc. - - Rec.), Gari (M. Mioc. - Rec.), Tellina (Lt. Olig. - - Rec.), Jouannetia (Lt. Eoc.), Pholadomya (M. Mioc.), Astele (M. Mioc. - - Rec.), Leiostraca (M. Mioc. - Rec.), Melanella (Lt. Mioc. - - Rec.), Calyptraea (E. Mioc. - - E. Plio.), Pterynotus (Lt. Eoc. - - Rec.), Pleuroploca (M. Mioc. - - Rec.), Athleta (Pal.), Bonellitia (Lt. Eoc. - - M. Mioc.).

Remarks Sea floor spreading and variation in sea water temperatures probably account for the fluctuation of the proportions of the four biogeographic elements with time. Following the splitting of f of the Australian plate from Antarctica in the Late Cretaceous, the former moved northwards towards the tropics into the Indo-Pacific Realm. Increasing numbers of Indo-Pacific genera migrated into the Southern Australian Region, leading to a maximum in generic diversity in the Middle Miocene. Dorman's (1966) paleotemperature curve for southeastern Australia has its maximum in the Middle Miocene in general agreement with the evidence from the molluscs. Zinsmeister !1982) has pointed out that Dorman's curve is at variance with that accepted for the Southern Ocean, which indicates a progressive downward trend in temperature through the Tertiary, and concludes that the northward drift of Australia was sufficient to counter this trend, a conclusion supported here. From the Middle Miocene to the present, Dorman's paleotemperature curve shows an overall decline in temperature, which is also reflected in the decline of numbers of IndoPacific genera and decrease in generic diversity in the study area. Overall, however, the proportions of the Tethyan Indo-Pacific and Endemic Elements have increased with time at the expense of the Australian-New Zealand and Cosmopolitan Elements, as the

ALCHERINGA

Australian plate moved away from the Antarctic and its southern circum-Pacific Paleoaustral Faunas, in keeping with Zinsmeister's conclusions, based on his study of southern circum-Pacific faunas.

Nature of the Tertiary sequence

Though Abele et al. (1976) have given a recent account of the Tertiary sequence in Victoria, some comments on the nature of the stratigraphical record and the occurrence of molluscs in it are pertinent as background t.o an understanding of gaps in the sequence of M ollusca. Singleton (1965) noted that, whilst the entire Tertiary succession is represented in Victoria, no single section is complete and part is non-marine. In addition, outcrop is often poor, so that only a composite section, based, in many cases, on short isolated sections or even individual outcrops, may be drawn up on which to base the succession of molluscan assemblages. Details of the assemblages and evidence for their relative superposition are given below under the definitions of each assemblage. Very broadly, the Tertiary rocks may be considered the products of a marine transgression initiated in the Paleocene and culminating in the Early to Middle Miocene, and a later regression which began in the Middle to Late Miocene and finished in the Pliocene. Sediments were deposited in four major basins, the Otway, Bass, Gippsland and Murray Basins (Fig. 1). The Bass Basin is situated offshore and is not discussed here, nor is the Murray Basin, as the exposed portion of the sequence in it has not been used in the compilation of the sequence of faunas, owing to the absence of suitable molluscan faunas. Singleton (1965) outlined three depositional environments - - coal measures, marine deltaic and normal marine, here referred to as 1, 2 and 3 respectively. In summary, he stated that the coal measures (1) are represented by conglomerates, sands, clays and coal seams ranging in age from Paleocene to Early Miocene and lacking marine fossils. The marine deltaic environment (2) is represented by carbonaceous, pyritic clastics deposited rapidly under anaerobic conditions. A benthonic fauna is absent except in thin intercalations

ALCHERINGA

of better aerated sediments. Molluscs are present only as poorly preserved moulds. Sediments of this environment range in age from Paleocene to Early Oligocene and occur, either overlying, or seaward of the earlier or contemporaneous coal measures formed on the adjacent land. The normal marine sediments (3) were divided by Singleton into shallow water neritic, characterised by bryozoal limestones with echinoid-brachiopod-pectinid faunas (3a), and slightly deeper water neritic with marls and clays containing rich molluscan faunas (3b). From Paleocene to Early Oligocene the normal marine deposits are localised, however, as the marine transgression progressed in the Late Oligocene, normal marine sediments became widespread reaching a maximum extent in the Miocene. During the Late Miocene, the basins began to fill up leading to deposition of regressive shallow water sands and clays through into the Early Pliocene. The sea retreated from all areas, but in the Gambier Embayment o f the Otway Basin, a separate transgression and regression in the Late Pliocene and Early Pleistocene was responsible for deposition of shallow water shell beds and limestones. Having given Singleton's broad outline, the sequence is now described in more detail with particular reference to the fossil localities. The Paleocene Pebble Point Formation, of marginal marine and nonmarine origin, covers a wide area of the Otway Basin, but outcrop, in general, is restricted to the Moonlight Head-Gellibrand River coastline and the valleys of the Wannon and Glenelg Rivers. Only in the first area can the outcrop be considered good. On the coast, the Pebble Point Formation is about 38 m in thickness and consists, in the main, of glauconitic quartz sandstone and conglomerate (Abele et al. 1976). Molluscs are restricted to a thin (0.5 m) band within the formation, preservation is frequently poor and the fauna is restricted in species. Molluscan assemblage I, Pebble Point, is based on this fauna. Conformably overlying the Pebble Point Formation is the Late Paleocene to Early Eocene Dilwyn Formation, consisting of approximately 150 m of dark carbonaceous sands, clays and silts. The unit is of marine deltaic origin (Singleton's second depositional environment) and molluscs are rare, being confined to three thin poorly


95

exposed units, the Rivernook Member and the Turritella and Trochocyathus bands. Molluscs can only be collected from one coastal locality of limited outcrop for each unit and no molluscs are known in the other outcrops of the Dilwyn Formation in the Glenelg River region of Western Victoria. Molluscan assemblage II, Rivernook Beach, is based on the faunas of the Rivernook Member and the Trochocyathus band. The time gap between Molluscan assemblages I and II is quite considerable and further complicated by the difference in facies. The only outcrops of Eocene to Early Oligocene sediments yielding good molluscan faunas are found in the Aire River and Johanna River districts, north-west of Cape Otway. The oldest unit in this area, the Paleocene Rotten Point Sand, is of nonmarine origin. The succeeding unit, the Eocene Johanna River Sand is, in part, equivalent to the Dilwyn Formation and is of similar origin and lithology (Singleton's second depositional environment), but no molluscs have been found in the rather limited outcrop of the formation. Thus there are no Early to Middle Eocene molluscan faunas known from the Otway Basin and it is not possible for any lineages to be extended back beyond the Late Eocene to the Paleocene with any degree of confidence. Conformably overlying the Johanna River Sand is the Late Eocene Browns Creek Clay. This formation was deposited in marine conditions on the continental shelf (Singleton's third depositional environment) and has fossils scattered throughout its 43 m thickness, but there are rich concentrations of bivalves and gastropods near its base and near the top of the formation. Outcrop, however, is limited. The rich and varied fauna constitutes the first of a succession of rich faunas preserved in Tertiary rocks through to the Pleistocene. Molluscan assemblages III (Browns Creek 1) and IV (Browns Creek 2) occur in this formation. The Browns Creek Clay grades vertically into the Castle Cove Limestone, an impure limestone of shallow water origin (Singleton's third depositional environment bryozoal limestones). Molluscan fossils are rare and the fauna is low in diversity. The Castle Cove Limestone is Late Eocene to Early Oligocene in age (Abele et aL, 1976). Conformably overlying the Castle Cove Limestone is the lower Glen Aire Clay, a unit of dark brown to grey sands and clays with a rich molluscan fauna. Outcrop is

T.A. DARRAGH

confined to small exposures in the valley of Duck Creek and the coast at Castle Cove (Locality No. AW5) and Point Flinders (AWl); however, at the latter locality, molluscs are very common. The age of this formation is Early Oligocene (Abele et al., 1976), Molluscan assemblage V, Point Flinders, occurs in this unit. The gap between assemblages IV and V is not great and the facies are similar. Succeeding Oligocene units in the Aire District are either poorly exposed or consist of bryozoal limestones, poor in gastropods and bivalves; therefore to continue the sequence of faunas another area must be considered. The only area of Oligocene sediments in Victoria, yielding good gastropod and bivalve faunas, is in the Torquay Sub-Basin on the northeastern flanks of the Otway Ranges. Here the sequence of rock types follows Singleton's broad outline, given above, and is somewhat similar to that of the Aire District. The oldest unit, the Paleocene to Late Eocene Eastern View Formation (Singleton's first depositional environment), has no marine fossils and is overlain by the Late Eocene to Early Oligocene Demons Bluff Formation (Anglesea Sand of Singleton, 1965), from which no well preserved molluscs are known. At Addiscot Beach, southwest of Bell Headland, the Late Oligocene Demons Bluff Formation is overlain conformably by the Angahook Formation, which at this locality is a dark grey, sparsely fossiliferous clay with concretionary limestone bands, transitional between the Demons Bluff Formation and the Jan Juc Formation. Outcrop is confined to a small exposure on the coast and the molluscan fauna is low in diversity. Molluscan assemblage VI, Addiscot Beach, occurs in this unit. The gap or break between assemblages V and VI is not known with any degree of precision. Overlying the Angahook Formation at Bell Headland is a thin tongue of the Jan Juc Formation. The contact is usually covered with beach sand, but is conformable (O.P. Singleton pers. comm.). The Late Oligocene to Early Miocene Jan Juc Formation consists of richly fossiliferous marl, calcarenite and clays deposited in open marine shelf conditions and crops out continuously from Rocky Point to Bird Rock, a distance of 2.5 km laterally. T o the southwest, the Jan Juc Formation passes laterally into the Point Addis Limestone, a bryozoal calcarenite

ALCHERINGA

containing an echinoid-brachiopod-pectinid macrofaunal assemblage. The molluscan fauna of the Jan Juc Formation is rich in numbers of species and individuals and the fauna is reasonably well known. Unfortunately, there are no other outcrops of similar age in southeastern Australia which contain a similar fauna. In contrast, bryozoal calcarenites are quite widespread. Molluscan assemblage VII, Bird Rock, occurs in the Jan Juc Formation. Conformably overlying the Jan Juc Formation is the Early Miocene Puebla Formation which crops out in the cliffs between Bell Headland and the mouth of Jan Juc Creek. Only the lower part of the formation, at the southwestern end of Jan Juc Beach near Bird Rock, is readily accessible and yields relevant molluscs. The Puebla Formation is a grey clay with thin limestone bands and molluscs are sparse. Outcrop is very limited and, consequently, the fauna is not well known. Molluscan assemblage VII1, Jan Juc Beach, occurs in this unit. Above the formation, sediments become increasingly carbonate-rich, molluscs become rarer and belong to the echinoid-brachiopod-pectinid macrofaunal assemblage (Cellepora beds, Zeally Limestone and Yellow Bluff beds). Molluscan assemblages VI, VII and VIII are based on faunas occurring in a continuous sequence of rocks, but the faunas upon which VI and VIII are based are rather poorly known and it is difficult to select key genera and species to define them. As it is not possible to base succeeding assemblages on the faunas of the formations above the Puebla Formation, another sequence must be used. The Early Miocene Fishing Point Marl, the youngest part of the section in the Aire District, succeeds the Oligocene Glen Aire Clay and Calder River Limestone, but the base o f the formation is not exposed. It is a grey marl with intercalated clays and bands of calcarenite. Bivalves and gastropods are reasonably common and diverse in the clays and marls, but outcrops which yield reasonable collections of molluscs are confined to the north shore of Lake Craven. Molluscan assemblage IX, Fishers Point, occurs in the basal part o f the outcrop and Molluscan Assemblage X, Boornong Road, occurs in the upper. There are no other known localities in southeastern Australia which yield good molluscan faunas equivalent in age to that occurring in the lower part of the formation; however, there are many

ALCHERINGA

localities of similar age to the upper part which yield good molluscan faunas. The gap between assemblages IX and X is thought to be small. As mentioned earlier, the Tertiary transgression culminated in the late Early Miocene and deposits of clays, silts, marls and limestones of the Heytesbury Group, and equivalents were deposited in open marine conditions, blanketing large areas of the Otway Basin and covering much of the older Paleogene sediments. The clays and marls contain rich molluscan faunas which can be easily collected from a relatively large number of localities, ranging from the Glenelg River in western Victoria as far east as Port Phillip. The relevant formations of the Heytesbury Group are the Myaring Beds, Muddy Creek Formation, Gellibrand Formation and Fyansford Formation. Molluscan Assemblages X, Boornong Road, XI, Balcombe Bay and XII, Gunyoung Creek, occur in these formations. The faunas are the most diverse of all in southeastern Australia and are comparatively well known. Assemblages IX to XII follow one another without significant gaps in the sequence. The best documented molluscan lineages are to be found through these assemblages. Younger formations of the Heytesbury Group are only preserved in the Otway Basin, as regression of the sea and tectonism have caused erosion of sediments deposited elsewhere. In the Port Campb611 area, the Gellibrand Formation is succeeded conformably by the Middle to Late Miocene Port Campbell Limestone, which is a fine grained limestone with the echinoidbrachiopod-pectinid macrofaunal assemblage in it. However, within the limestone there are clay rich beds, such as the Ruttledge Creek Member and that at Lake Bullenmerri, in which bivalves and gastropods are common. Molluscan Assemblage XIII, Lake Bullenmerri, is based on the fauna from the clay rich beds at Lake Bullenmerri. Late Miocene and Early Pliocene sedimentation occurred in a regressing sea as the margins of the basins began to fill with sediment. The sediments consist of sands, clays and shell beds deposited in open marine conditions, but in shallower water than the clays and marls of the Oligocene to Middle Miocene. Erosional breaks in the sequence are common; macrofossils tend to be concentrated in shell bands and much of


97

the original sequence has probably been eroded away. Ferruginisation with destruction of carbonate fossils, particularly in the Port Phillip area of the Otway Basin, makes precise identification of taxa difficult, if not impossible. There is a major break in the sequence of faunas owing to the difference in facies between deeper water Oligocene to Middle Miocene molluscan faunas and the Late Miocene to Pliocene shallow water molluscan faunas. It is, therefore, difficult to find genera which are common to both. Lineages are difficult, if not impossible, to trace from one to the other. Many genera, particularly gastropods, common through the earlier Tertiary, are either rare or absent in the late Tertiary, but do occur in living faunas on the continental shelf, for example Ternivoluta, Livonia, Umbilia, Austroharpa, Columbarium and Notovoluta. The Gippsland Basin has the nearest approach to a complete onshore sedimentary sequence through the Miocene and Pliocene, though much of the earlier part of the sequence is dominated by bryozoal limestones and relevant molluscs are absent. The oldest formation to crop out in this basin, the Early to Late Miocene Gippsland Limestone, consists of bryozoal calcarenite and marls which contain the characteristic echinoid-brachiopod-pectinid macrofaunal assemblage. It is succeeded by the Late Miocene Tambo River Formation in the Bairnsdale area. The lithology of the latter is transitional between the calcarenite of the Gippsland Limestone and the shelly sands of the succeeding Jemmys Point Formation. The echinoid-brachiopod-pectinid macrofaunal association is the dominant macrofaunal element in the Tambo River Formation, but locally and, in particular, near the top of the formation, there are more silty and sandy lenses in which bivalves and gastropods are common. Such a unit is the Rose Hill Marl Member at Moondarra Farm, upon the fauna o f which is based Molluscan Assemblage XIV, Rose Hill. There are no other known outcrops of suitable sediments in Victoria which could yield an appropriate fauna o f similar age. The time gap between this Assemblage and the preceding Assemblage XIII from the Otway Basin is not known with certainty. Conformably overlying the Tambo River Formation is the Late Miocene to Early Pliocene Jemmys Point Formation, but the contact between the two is not exposed and

98

T.A. DARRAGH

much of the lower part of the Jemmys Point Formation is known only from bores. Mollusca are known only from the upper part of the formation which crops out in the Lakes Entrance area. Outcrop here is good and molluscs are common and varied, so that the fauna is well known. Molluscan Assemblage XV, Bunga Creek, occurs in the lower part o f the outcrop and is succeeded by Molluscan Assemblage XVI, Jemmys Point, in the upper part. The gap between Molluscan assemblages XIV and XV is not known with certainty owing to lack of outcrop, but is thought to be small. The Jemmys Point Formation is overlain by non-marine sediments and no younger marine Tertiary rocks crop out in eastern Victoria. Other formations in the Port Phillip Basin, the Black Rock Sandstone and the Moorabool Viaduct Sand, and in the Otway Basin, the Grange Burn Formation, are equivalent, in part, to the Jemmys Point Formation and contain Molluscan Assemblages XV and XVI. These three formations disconformably overlie Heytesbury Group sediments and in turn are succeeded by non-marine sediments or are overlain by basalt. There are no diverse, well preserved faunas known from Victoria younger than that in the Jemmys Point Formation except for the Late Pliocene-Early Pleistocene faunas of the Glenelg River region. On Flinders Island in Bass Strait the Pliocene Cameron Inlet Formation has a fauna intermediate in age between these and has been used to complete the faunal sequence as Molluscan Assemblage XVII, Flinders Is. There are no equivalents on the mainland with the possible exception of the poorly known fauna of the Late Pliocene Whalers Bluff Formation at Dutton Way, Portland. The extent of the gap between Assemblages XVI and XVII is not known since the Cameron Inlet Formation laps on to basement rocks. The Pleistocene Memana Formation disconformably overlies the Cameron Inlet Formation. The youngest sediments to be considered are those which crop out on the Glenelg River near Dartmoor. Here, the Late Pliocene to Early Pleistocene Werrikoo Limestone disconformably overlies Heytesbury Group sediments. The Werrikoo Limestone consists of calcarenites, coquinas and sands deposited in very shallow water. Shell beds present throughout the for-

ALCHERINGA

mation, in general, contain large numbers of specimens of few species, in particular, of the genera Ostrea, Glycymeris and Pecten. Many of the aragonitic shells, if present, have been leached away. Only at the base of the formation is there a shell bed with a diverse fauna of bivalves and gastropods, the Werrikoo Shell Bed. Molluscan assemblage XVIII, Limestone Creek, is based on the fauna in the basal shell bed. The extent of the gap between this assemblage and the preceding from Flinders Island is not known with any precision but is thought to be small.

Faunal assemblages For each assemblage, a typical locality has been chosen, the fauna of which best typifies the assemblage. In selecting a typical locality, various factors have been used. These are 1. the position of the locality within the Tertiary sequence and the nature of the fauna it contains; 2. the availability of specimens of molluscs at a particular outcrop; 3. the geographical position of the outcrop with respect to other localities in the sequence; 4. facies represented at the locality. In some cases, no choice is possible since only one outcrop contains a particular fauna. In order to reduce the variable of geographical separation of faunas, an attempt has been made to establish the sequence within confined areas, the Otway Basin for the Paleocene to Middle Miocene part of the sequence and the Gippsland Basin for the Late Miocene to Early Pliocene part. The two Late Pliocene assemblages have, of necessity, been chosen from areas relatively isolated geographically from these two sequences. The effect of facies variation on molluscan faunas has been kept to a minimum by choosing localities with similar lithologies. It is believed, therefore, that the changes in faunal composition from one assemblage to another are mainly the result of changes in time and are not due to geographical separation or change in facies. Some control on this is available by checking against the foraminiferal zonation. For each assemblage, a reference is given to the stratigraphy of the area in which the type locality occurs and the evidence for superposition of each type locality within the

ALCHERINGA

sequence is cited. Where possible, the assemblage is tied into the foraminiferal zones proposed by Taylor (in Singleton, 1968), Carter (1964) and Mallett (1977). The localities correlated by means of this scheme are cited by the Museum of Victoria Tertiary fossil locality numbers. The list of the key genera and species of the assemblage is given under the headings 'First Appearances', 'Last Appearances' and 'Restricted Taxa'. The taxa chosen are those whose time ranges, particularly the first appearance, are well established and also, where possible, are those that have a wide geographical distribution, are reasonably common and are easily recognizable. However, it has not always been possible to abide by these criteria. It should also be borne in mind that only a fraction of the taxa has been investigated in taxonomic detail. The symbol * indicates the first appearance of the genus and + the last appearance. The stratigraphical ranges of the key taxa are indicated in the table at the end of the section. Molluscan Assemblage I - - Pebble Point This assemblage is based on the fauna in the Pebble Point Formation cropping out in the coastal cliffs between BuckleyPoint Pebble Point, Princetown, at locality numbers FL 3 and FL 4. Mollusca are confined to a 0.5 m bed of grit of limited outcrop about 10 m above the base of the formation. The stratigraphy has been described by Baker (1950). Specimens are difficult to collect from the hard matrix, and often are abraded or badly weathered, so that some identifications must be regarded as tentative, particularly as many species are known from only one or two specimens. The common elements in the fauna were described by F. A. Singleton (1943) and sufficient is known of the remainder to demonstrate that it has little in common with younger faunas of the Australian Tertiary. A few species range into the succeeding assemblage, but not higher in the stratigraphic column. The assemblage is of Middle Paleocene age and is referred to Taylor's Zone U. McGowran (1978) places this horizon within Zone P.3. Localities correlated with the type locality. PL1, Bell Point; FL2, southwestern side of


99

Pebble Point; FL5, Killara Bluff; FL6, Hazell Bank, Bahgallah; Grange Burn, 15 km west of Violet Creek; Park Hill, Wannon R.; Morgiana Estate, Wannon R. Key genera and species. First appearance. *Nuculana paucigradata, *Columbarium sp., *Gilbertina sp. Restricted. *Cucullaea psephea, *Eotrigonia paleocenica, Lahillia australica, *Aturoidea distans, *Eutrephoceras victorianum, Dentalium (Fissidentalium) gracilicostatum. Molluscan Assemblage II - - Rivernook This assemblage is based on the fauna present in the Rivernook Member of the Dilwyn Formation which crops out in the centre of Rivernook Beach about 2 km southeast of the mouth of the Gellibrand River at locality FL 7. The sediments there are dark green pyritic and limonitic sand and clay, 6 m thick about 30 m above the base of the Dilwyn Formation. The stratigraphical position of the bed has been discussed by Baker (1950). Outcrop of the member is poor and the few specimens of each species from it have been collected from a few boulders which have fallen on to the beach. There is a large endemic element in the undescribed molluscan fauna, so that it is not possible to compare it either with younger faunas, or even with that of the underlying Pebble Point Formation. This endemism is, at least in part, due to the ecological conditions under which the member was deposited. It represents a short period of sedimentation under shallow marine conditions with better aeration than the remainder of the sequence, in which sediments were generally deposited under conditions of poor water circulation. Superposition with respect to the preceding assemblage is demonstrated in the cliffs in the type area where the Dilwyn Formation conformably overlies the Pebble Point Formation, in which the preceding assemblage occurs. The assemblage is of Late Paleocene age and is referred to Taylor's Zones R and S. McGowran (1978) states that the Rivernook Member is no younger than Zone P.6. Localities correlated with the type locality. FL8, Rivernook Beach, northwest of track; FL9, AW7. Key genera and species. First appearance. *Poreleda sp., *Ennucula sp., *Bonnellitia sp.

100

T.A. DARRAGH

Last appearance. Nuculana paucigradata, + Gilbertina. Restricted. Athleta (,4) wangerrip.

ALCHERINGA

tatei, Ennucula tenisonL *Sacella chapmani, *Ledella leptorhyncha, *Notogrammatodon cainozoica, *Arcopsis dissimilis, Limopsis chapmani, *Notostrea lubra, Eotrigonia eocenica, Salaputium communis, *Caryocorbula pyxidata, *Myadora lamellata. Restricted. *Notovoluta capitonica, + Scaphella (A urinia) johannae.

Molluscan Assemblage I I I - - Browns Creek 1 This assemblage is based on the rich fauna in the lower 9 m of brown sandy clay of the Browns Creek Clay, immediately below the greensand in a gully close to the mouth of Browns Creek, Johanna, at locality number Molluscan Assemblage I V - Browns Creek FL 11. The stratigraphy is discussed by 2 Abele et al. (1976), but the molluscs have not been studied in detail. Identifications of This assemblage is based on the fauna in a described species have been made by the dark grey gritty clay of the Browns Creek Clay, 16 m above the greensand in a gully writer and are listed in Table 1. The assemblage has nothing in common close to the mouth of Browns Creek, with the preceding except for the occurrence Johanna, at locality number FL13. The stratigraphy is discussed by Abele et al. of the genera Poroleda, Ennucula, Cuspidaria, Acteon and Niso. The Browns (1976), but the molluscs have not been Creek 1 assemblage is the oldest markedly studied in detail nor listed previously. diverse fauna in the sequences discussed here Identifications of described species have and is closely related to succeeding faunas. been made by the writer and are listed in Many genera make their first local ap- Table 1. This assemblage has much in pearance here and continue through the common with the preceding and a number of Tertiary, some to the present. Unlike the forms present in both assemblages do not preceding assemblage, the proportion of occur higher in the stratigraphic record. Superposition with respect to the endemic or restricted genera is low. Superposition with respect to the preceding assemblage can be directly preceding assemblage can only be demonstrated in the section at the type established indirectly. The Browns Creek locality. The assemblage is of Late Eocene age and Clay overlies the Johanna River Sand which can be correlated with part of the Dilwyn is referred to Taylor's Zone L (Carter's Unit Formation on the basis of Foraminifera, 2). McGowran (1978) places this part of the Browns Creek Clay in Zone P.16. spores and pollen (Abele et al., 1976). The assemblage is of Late Eocene age and Localities correlated with the type locality. is referred to Taylor's Zone N. McGowran FL 10, Blanche Point, South Australia; FL (1978) places this part of the Browns Creek 14, washout nearest Johanna River; FL 16, Clay in P. 15. Castle Cove; FL 17, Great Ocean Road, No other locality with this assemblage is Hamilton Creek; Thomson Road near known in outcrop. Walpole, Western Australia. Key genera and species. First appearance. Key genera and species. First appearance. *Spirocolpus aldingae, *Jetwoodsia nullar*Semitrivia pompholugota, *Proterato ausborica, *Orthochetus pagoda, *Notacirsa tralis, Colurnbarium calcaraturn, Alcithoe lampra, *Archierato pyrulata, *Ellatrivia (Waihaoia) cribrosa, *Dosina multilameltorquayensis, * Willungia ovulatella, lata. *Cypraedia clathrata, *Friginatica Last appearance. Jetwoodsia nullarborica, aldingensis, *Ratifusus nodulatus, + Orthochetus pagoda, + Cypraedia clath'Austrotriton " cribrosa, *Pteropurpura bifrons, Pteropurpura calva, *Enatimene rata, + Ampullina effusa, 'Austrosassia' cribrosa, Laevityphis ludbrookae, monotropis, *Laevityphis ludbrookae, *Dennantia aldingensis, *Austrolithes in- Enatimene monotropis, Dennantia aMingencompositus, *Fusinus sculptilis, Tectifusus sis, Fusinus sculptilis, + Tectifusus aldinaldingensis, *A ncillista subgradata, gensis, Ancillista subgradata, Notopeplum Ledella leptorhyncha, *Gracilispira ligata, *Alcithoe (*Waihaoia) protorhysum, + Arcopsis dissimilis. pagodoides pagodoides, *Notopeplum protorhysum, *Triploca ligata, *Nucula Restricted. Ataxocerflhium concatenatum,

ALCHER1NGA

*Oamaruia ptychotropis, *Semitriton varicosum, *Gennoliva adelaidae, Conorbis atractoides, *Arca pseudonavicularis, *Barbatia limatella, *Curia radiata.


101

Molluscan Assemblage V I Addiscot Beach This assemblage is found in a dark grey pyritic sandy clay in the basal 4 m of the Angahook Formation cropping out at Addiscot Beach near Bell Headland, locality Molluscan Assemblage V -- Point Flinders number FL 23. The stratigraphy has been This assemblage is based on the fauna in the discussed by Raggatt & Crespin (1955) and lower Glen Aire Clay, a dark grey, richly Singleton (1968). Outcrop is very limited and fossiliferous clay, cropping out at the the sediments are not richly fossiliferous. southeastern end of Station Beach near Superposition with respect to the Point Flinders at locality number FL 19. The preceding assemblage can only be stratigraphy has been discussed by Carter established indirectly. The basal part of the (1958). Outcrop is not good and the Angahook Formation at Addiscot Beach is stratigraphical relationships of the outcrop conformable on the Anglesea Member of the are not clear owing to slipping of sediment Demons Bluff Formation which, in part, is and sand cover, but the molluscan fauna is correlated with the Browns Creek Clay and well known. Identifications of described the Glen Aire Clay. species are listed in Table 1 for comparison The assemblage i.s of Late Oligocene age with the Late Eocene faunas, but there is a and is referred to Taylor's Zone J (Carter's large number of undescribed taxa present. Unit 4). In terms of the Australian stages, Superposition with respect to the the assemblage is immediately prepreceding assemblage can be demonstrated Janjukian. indirectly by correlation of this outcrop with No other localities with this assemblage the nearby Castle Cove section where the are known in outcrop. Glen Aire Clay overlies the Castle Cove Limestone, which in turn overlies the Key genera and species. First appearance. cribarioides, * Umbilia Browns Creek Clay containing the Browns * Cerithiella platyrhyncha, * Typhis maccoyi, ColumCreek 2 Assemblage (IV). uniliratum, Murexsul eyreL The age of the assemblage is probably barium * Belophos cancellata, * Liratomina inEarly Oligocene (Abele et al., 1976), though previous writers, (e.g. Darragh, 1971), have tertexta, Cochlespira venusta, Apiotoma tended to regard the lower Glen Aire Clay as pritchardi, Apiotoma janjukiensis. Last appearance. + Spirocolpus aldingae, latest Eocene. The assemblage is referred to Taylor's Alcithoe (Waihoaia) pagodoides pagodoides. Zone K (Carter's Unit 3). Localities correlated with the type loca#ty. FL 20, AW 4, Aire Coast; FL 21, Duck Molluscan Assemblage VII-- Bird Rock Creek. This assemblage is based on the fauna of the Jan Juc Formation cropping out in the Key genera and species. First appearance. coastal cliff between Fisherman Steps and *.4ustrea hudsoniana, "Anadara' interclathBird Rock, Torquay at locality number FL rata, Venericardia janjukiensis. 24. Lithology is varied, ranging from Last appearance. Notacirsa lampra, glauconitic clayey silts through marls to Proterato australis, Archierato pyrulata, glauconitic calcarenite. The stratigraphy is Semitrivia pompholugota, Columbarium summarised by Singleton (1968) and Abele et calcaratum, Pteropurpura bifrons, al. (1976). Outcrop is excellent, the Pteropurpura calva, Austrolithes in- sediments are richly fossiliferous, and the compositus, Alcithoe (Waihaoia) cribrosa, fauna is reasonably well known. The + Triploca ligata, Ledella leptorhyncha, assemblage marks the entry of a large + Notostrea lubra, Eotrigonia eocenica, number of genera, particularly from the Myadora lamellata. Indo-Pacific region, into southeastern Restricted. *Collonista otwayensis, Ptero- Australia, though only those genera chelus otwayensis, Notopeplum primaru- regarded as being of biostratigraphic significance are listed here. gatum, Athleta (*Ternivoluta) curvicostata, Superposition with respect to the + Semitr#on dennantL *Apiotoma bassi, preceding assemblage can be directly *Borsonia protensa.

102

T.A. DARRAGH

established in the section exposed at Addiscot Beach and Bell Headland where the lower part of the Jan Juc Formation conformably overlies the Angahook Formation (Singleton, pers. comm.). The assemblage is of Late Oligocene to Early Miocene age and is referred to Taylor's Zone 1 (Carter's Unit 5). In terms of the Australian stages the assemblage is type Janjukian. Localities correlated with the type locality. FL 26, Barwon River, south of Birregurra; FL 27, Moorabool River, south of Maude. Key genera and species. First appearance. * Zoila sp., * Austrocypraea contusa, * Rhynchocypraea leptorhyncha, * Antephalium sufflatus, Sassia abbotti, Ericusa pellita, * Livonia stephensi, Bonellitia varicifera, Conus pullulescens, Conus dennanti, Conus cuspidatus, Conus heterospira, Nototerebra tenisoni, *Nannamoria weldii, Cucullaea corioensis, Eotrigonia tubulifera, Eotrigonia subundulata, Tellina cainozoica, Solecurtus legrandi, Hina cainozoica, *Proxichione hormophora, Tawera propinqua, Clavagella majorina. Last appearance. "Anadara' interclathrata, Dosina multilamellata, Columbarium uniliratum. Restricted. *Gigantocypraea gabrieli, *Galeodea wilsoni, Personella interposita, Austrofusus selwyni, *Zemira tessellata, *Austroharpa pachycheila, Athleta (Ternivoluta) anticingulata, Ericusa macroptera, Alcithoe (Waihaoia) pagodoides sororcula, Alcithoe (Waihaoia) pueblensis, Alcithoe (Waihaoia) neglectoides, Spissatella maudensis, Trachycardium pseudomagnum, Proxichione etheridgei, *Diplodonta harrisi, *Phragmorisma anatinaeformis.

Molluscan Assemblage VIII - - Jan Juc Beach This assemblage is based on the molluscan fauna in the lower 20 m of the Puebla Formation, a grey pyritic clayey silt with bands of hard dark grey limestone, at the southwestern end of Jan Juc Beach, Torquay, locality number FL 23. The stratigraphy has been discussed by Raggatt & Crespin (1955) and Singleton (1968). Outcrop is poor and macrofossils are sparsely distributed; consequently knowledge of the fauna is poor. Nevertheless, sufficient is known to define the assemblage and demonstrate its distinctive character.

ALCHERINGA

Superposition with respect to the preceding assemblage can be directly demonstrated at the type locality, where the Puebla Formation conformably overlies the Jan Juc Formation. The assemblage is of Early Miocene age and is referred to Taylor's Zone H (Carter's Unit 6). In terms of the Australian stages, it is Longfordian. Localities correlated with the type locality. FL 33, Barwon River at Birregurra. Key genera and species. First appearance. * Notadusta victoriana, Baryspira tatei, Zemira australis antecursoria, Ericusa atkinsoni, Livonia spenceri, Alcithoe (Waihoaia) sarissa, Noto voluta linigera. Last appearance. Nannamoria weldii. Restricted. A thleta (Ternivoluta) craticula.

Molluscan Assemblage I X -- Fishers Point This assemblage is based on the fauna in the lower part of the Fishing Point Marl, a grey and brown marl with local lenses of brown calcarenite, cropping out in the cliff to the southeast of Fishers Point, Horden Vale, at locality number FL 35. The stratigraphy has been discussed by Carter (1958). The marl is richly fossiliferous, but outcrop is poor except in fresh landslips. Superposition with respect to the preceding assemblage can only be established indirectly on the basis of Carter's (1958) correlation of the Fishing Point Marl with the upper part of the Puebla Formation. The molluscan assemblage does, however, have elements which make their first appearance here and continue into younger assemblages. The assemblage is of Early Miocene age and it is referred to Taylor's Zone G (Carter's Unit 7). In terms of the Australian stages it is Longfordian. Loca#ties correlated with the typical locality. FL 34, southern bank of Lake Costin; FL 36, northwest of Red Hill; FL 37, Camping Reserve, Horden Vale. All these localities are within 1.5 km of the type locality and no other occurrences of the assemblage are known. Key genera and species. First appearance. *Serratifusus scabrosus, Zoila mulderi, *Subpterynotus wallacei, Typhis evaricosus, Notopeplum maccoyi translucidum, Athleta (Ternivoluta) antiscalaris antiscalaris, Limopsis morningtonensis.

ALCHERINGA

Last appearance. Umbilia platyrhyncha, Sassia abbotti, Ericusa atkinsoni, Notovoluta linigera. Restricted. Ternivoluta subcrenulifera, Nannamoria f asciculata.

Molluscan Assemblage X -- Boornong Road This assemblage is based on the fauna occurring in the Gellibrand Formation, a grey calcareous silt, exposed in a cutting on Boornong ( = Steen's) Road, Cooriemungle at locality number FL 48. Outcrop at the type locality is limited, but the sediment is reasonably fossiliferous and has yielded a good fauna. It has been chosen as type locality because the outcrop will probably always yield a reasonable collection of molluscs, whereas other localities, which could have been used, have become either weathered and overgrown with vegetation, or are sparsely fossiliferous. The stratigraphy of the area has not been examined in detail, hut general information on the Gellibrand Formation is available in Abele et al. (1976) and Glenie (1971). Macumber (1966) discusses, in general terms, the stratigraphy and structure of the area in connection with the nearby Waarre No. 1 bore. This bore, situated 1 km south o f the type locality of the assemblage, struck Narrawaturk Marl (Taylor's Zone 1) at 17 m after penetrating alluvial valley fill. The evidence suggests that the type locality is close to the base o f the Gellibrand Formation. Superposition with respect to the preceding assemblage can be demonstrated indirectly by correlation. The assemblage has been recognised at the top of the outcrop of the Fishing Point Marl at FL 50, top of Fishers Point, where it overlies strata either laterally equivalent to, or a little younger than, the strata at the type locality of the preceding assemblage. The assemblage is of Early Miocene age and it is referred to Taylor's Zone F (Carter's Unit 8 or 9). On the basis of Carter's (1958) determination o f the age of the upper part of the Fishing Point Marl, the assemblage is Batesfordian. The assemblage is present at locality FL 38, Curlewis, which was assigned to the late Longfordian or Batesfordian by Abele et al. (1976). For the purposes of this account, the writer regards the assemblage as being of Batesfordian age. Localities correlated with the type locality.


103

FL 38, Ad 14, Curlewis; FL 39, Ad 12, Moolap; FL 40, Belmont shaft; FL 41, Amphitheatre, Yarrowee (Leigh) River; FL 42, south of Amphitheatre, Yarrowee River; FL 43, cutting 1.2 km south o f Kennedy's Creek; FL 44, Chapple's Locality, La Trobe River; FL 45, cutting 0.6 km south o f Kennedy's Creek; FL 47, 4.5 km cutting, Simpson-Princetown Road; FL 49, cutting, Serpentine Creek; FL 50, top of Fishers Point; FL 51, Devils Den, Glenelg River; FL 54, Skinners, Mitchell River. Key genera and species. First appearance. Gigantocypraea gigas, *Palliocypraea gastroplax, Umbilia eximia, *Biplex maccoyi, *Austrotriton sp., Typhis acanthopterus, Penion roblini simulans, Lyria acuticostulata, Nannamoria strophodon, *Cancellaphera calvulata, Limopsis maccoyi, *Crassatella dennanti. Last appearance. Zoila m ulderi, Zemira australis antecursoria, Ericusa pellita, Athleta (Ternivoluta) antiscalaris antiscalaris. Restricted. Serratifusus bovarius, *Hispidofusus piscatorius, *Solutofusus curlewisensis, Nannamoria deplexa, Notovoluta differta.

Molluscan Assemblage X I - - Balcombe Bay This assemblage is based on the fauna occurring in the Fyansford Formation ( = Balcombe Clay), a richly fossiliferous grey silt, at Fossil Beach, 3 km south of Mornington, locality number FL 78. Outcrop is limited to the shore platform, but has yielded a good fauna which is well known. The stratigraphy is described by Gostin (1966). Superposition with respect to the preceding can be established indirectly by correlation. The two Assemblages X and XI occur in cuttings o f the Princetown - Simpson Road on the flanks of the Ferguson Hill uplift. Here the Gellibrand Formation dips at a low angle to the southeast. The older Boornong Road Assemblage (X) occurs in the cutting at FL 47 and the Balcombe Bay Assemblage (XI) in a cutting downdip 0.5 km to the southeast. The assemblage is of Middle Miocene age and it is referred to Mallett's Zones V8 and V9 (Carter's Unit 10). In terms of the Australian stages, the assemblage is type Balcombian. Localities correlated with the type locality. FL 56, cutting 4 km north of Ocean Road;

104

T.A. DARRAGH

FL 57, Roberts Dam, 6.5 km south of Simpson; FL 58, cutting Waarre Road, Waarre; FL 59, Great Ocean Road, 1.9 km north of Princetown; FL 60, Smith's Dam, lot 393; FL 61, Gully, Eastern Creek, 0.75 km east of Port Campbell Road; FL 62, cutting, Cooriemungle Road, south of Guys Road; FL 63, cutting, Ford and Latrobe Road junction; FL 64, cutting, Eastern Creek Road, ½ km east of Port Campbell Road; FL 66, cutting Port CampbellTimboon Road, 0.75 km south of Eastern Creek Road; FL 67, southeast of rocks at southeastern end of Gibson Beach; FL 68, southeastern end of Gibson Beach; FL 69, Red Bluff, Shelford; FL 70, Farrell's, Yarrowee River; FL 71, Native Hut Creek, southwest of Glenleigh; FL 72, Ad 28, Orphanage Hill, Fyansford; FL 73, southeast Trunk Sewer, south side Centre Dandenong Road; FL 74, shaft, corner of Junction and Boundary Roads; FL 75, southeast Trunk Sewer; FL 76, Earmil Creek; FL 77, Altona Bay Coal Shaft; FL 79, Upstream section, Gunyoung Creek; FL 80, Dryden Farm, Moorabool River; FL 81, overburden, Batesford Quarry; FL 82, Clifton Bank, Muddy Creek; FL 84, Cadell Marl, 4.8 km south of Morgan. Key genera and species. First appearance. Zoila platypyga, Sigaretotrema subinfundibulum, A ustrotriton woodsi, Penion Iongirostris, Athleta (Ternivoluta) antiscalaris levior, *Amoria costellifera, Livonia hannafordi. Last appearance. Livonia spenceri. Restrticted. Austrotriton textilis, Serratifusus foliaceus, Serratifusus craspedotus, Solutofusus carinatus, Lyria harpularia, Ericusa hamiltonensis, Notovoluta cathedralis, Bathytoma rhomboidalis.

Molluscan Assemblage X I I Gunyoung Creek This assemblage is based on the molluscan fauna in the richly fossiliferous 15 m of Fyansford Formation (= Balcombe Clay) outcropping at the mouth of Gunyoung (= Grices) Creek at locality number FL 103. The stratigraphy is discussed by Gostin (1966). Superposition with respect to the preceding assemblage can be demonstrated directly. The Balcombe Bay Molluscan Assemblage (XI) occurs in the upstream section of Gunyoung Creek, approximately

ALCHERINGA

20 m below the type locality of the Gunyoung Creek Assemblage (Gostin, 1966, fig. 3). The assemblage is of Middle Miocene age and is referred to the upper part of Mallett's Zone V10 (Carter's Unit 11). In terms of the Australian stages, the assemblage is Bairnsdalian. Localities correlated with the type locality. FL 88, northwestern end of Gibson Beach; FL 89, Track to Quarry, Curdie; FL 90, Timboon-Scott's Creek Road, 2.4 km northeast of Timboon; FL 91, Opposite Timboon shops; FL 92, Timboon-Port Campbell Road, 100 m south of Timboon; FL 95, Western Beach, Corio Bay; FL 96, Yarrowee River, north of Inverleigh; FL 97, Sect. 2B, Murgheboluc; FL 98, Native Hut Creek, south of Highway; FL 99, junction of Barwon River and Native Hut Creek; FL 100, Murgheboluc 4A; FL 101, North Shore, Corio Bay; FL 104, Manyung Rocks. Key genera and species. First appearance. Serratifusus stellatus, Nannamoria lhnbata, Bathytoma decomposita. Last appearance. Zoila platypyga, Rhynchocypraea leptorhyncha, Umbilia eximia, Biplex maccoyi, Athleta (Ternivoluta) antiscalaris levior, Cymbiola macdonaldi, Crassatella dennanti, Proxichione subtilicostata, Penion roblini simulans, Lyria acuticostulata. Restricted. Serratifusus clydoniatus.

Molluscan Assemblage XIII - - Lake Bullenmerri This assemblage is based on the molluscan fauna in the Gellibrand Formation cropping out on the northwestern side of Lake Bullenmerri near Camperdown at locality number FL 87. The lithology is a yellow to blue-grey calcareous silt, moderately rich in molluscs, bryozoans and corals. Outcrop is limited to the shore of the lake and the stratigraphical relationships of the outcrop are not clear, but it has yielded a good fauna and, therefore, it has been chosen as the type locality. Superposition with respect to the preceding assemblage can be demonstrated indirectly by correlation with locality FL 93, Rutledge's Beach, where the assemblage occurs in the Rutledge Creek Member of the Port Campbell Limestone. This member is 102 m above the top of the Gellibrand Formation (Mallett, 1977) at FL 88, north-

ALCHERINGA

western end of Gibson Beach, where Molluscan Assemblage Xll occurs. The assemblage is of late Middle Miocene age and it is referred to Mallett's Zone V12. In terms of the Australian stages, the assemblage is Bairnsdalian. Localities correlated with the type locality. FL 93, Rutledge Beach; FL 94, Amphitheatre, Ingles Creek; FL 85, Lake Keilambete, Terang; FL 86, Lake Gnotuk, Camperdown; FL 102, Warrambine Creek; FL 108, Drcier's Cliff, Mitchell River. Key genera and species. First appearance. Umbilia tatei, Athleta (Ternivoluta) antiscalaris antispinosa, *Neotrigonia acuticostata, Proxichione moondarae. Last appearance. Typhis laciniatus, Serratifusus stellatus, Amoria costellifera, Livonia hannafordi, Bathytoma decomposita, Nannamoria limbata, Ericusa ancilloides, Alcithoe (+ Waihaoia) sarissa, Eotrigonia tubulifera. Molluscan Assemblage X I V - - Rose Hill This assemblage is based on the fauna in the Rose Hill Marl Member of the Tambo River Formation, a calcareous silt with scattered shells, cropping out at Moondarra Farm on the left bank of the Mitchell River near Bairnsdale, locality number FL 111. The stratigraphy of the site has been discussed by Wilkins (1963). Outcrop at this locality is poor, but adequate collections have been obtained by excavation. Superposition with respect to the preceding assemblage can be established indirectly by correlation. The Rose Hill Marl Member conformably overlies the Bairnsdale Limestone at locality FL 111. On the opposite bank of the Mitchell River at locality FL 108, Dreiers, the Bairnsdale Limestone conformably overlies the top of the Wuk Wuk Marl containing molluscan assemblage XIII. The assemblage is of Late Miocene age and is referred to Mallett's Zone V 13. In terms of the Australian stages it is MitcheUian. Key genera and species. First appearance. Polinices subvarians, A ustrotriton garrardi, Phos gregsoni, *Alocospira orycta, Tucetona convexa, Bassina paucirugata, Nannamoria paraboloides, Austrotriton bassL *Bedeva approximans, Belloliva nymphalis, Amoria undulata, Neotrigonia howitti, *Placamen subroboratum, Micantapex pritchardi.


105

Restricted. *Tylospira clathrata, Eucrassatella rosicollina.

Molluscan Assemblage X V - - Bunga Creek This assemblage is based on the fauna in the Jemmys Point Formation cropping out in the lower 4.5 m of the road cutting on the northeastern side of Bunga Creek near Lakes Entrance at locality number FL 114. The stratigraphy of this site has been discussed by Wilkins (1963). The lithology is a fawn calcareous silty sand with abundant molluscan shells and shell fragments. Superposition with respect to the preceding assemblage cannot be established directly in outcrop. The Jemmys Point Formation overlies the Tambo River Formation in which the preceding assemblage occurs, but this relationship has only been established in bores (Abele et al., 1976). The age of the assemblage, for the purposes of this study is regarded as Late Miocene though the type locality is considered by Mallett (1977) to be of Early Pliocene age. Other localities correlated with the type locality such as FL 130, Beaumaris, are regarded by Mallett as Late Miocene. The assemblage is referred to Mallett's Zone V 14A, but at other localities, it is referred to Mallett's Zone V 12 or 13. Precise relationships of all localities correlated with the type locality are still in doubt. In terms of the Australian stages, the assemblage is Cheltenhamian. Localities correlated with the type locality. FL 115, Lake Bunga crossing; FL 116, Old Highway, Bunga Creek; FL 118, Mississippi Creek Tramway cutting; FL 119, Ritchie's Cutting, Scrivenor's Road; FL 120, John St, Lakes Entrance; FL 121, North Arm, at Hunters Road; FL 122, North Arm, south of Hunter Gully; FL 123, North Arm, below Ferndale Parade; FL 124, North Arm, north of Hunter Gully; FL 125, North Arm, eastern Bank, opposite Hunter Road; FL 126, North Arm, below Nautilus Way; FL 127, Mississippi Creek Tramway Terminus; FL 128, Bunga Creek tributary, allotment 147; FL 129, 12.2 m below Wright St., Bentleigh; FL 130, Beaumaris; ?FL 131 Moorabool Viaduct; FL 132, Spring Creek, Minhamite; FL 133, Murray River Cliff, Wookool Bend: ?FL 134, Loxton Pumping Station. Key genera and species. First appearance. Tylospira coronata, Nassarius crassigranosus, Penion spatiosus, Fusinus gipps-

106

T.A. DARRAGH

landicus, Costellaria euglypha, Ericusa sowerbyL Sydaphera wannonensis, Gemmaterebra subcatenifera, Ennucula kalimnae, Chlamys meringae, Cardita kalimnae. Last appearance. Sigaretotrema subinfundibulum. Restricted. Tylospira lirata, A thleta (Ternivoluta) bungae, Eucrassatella dorsennata.

ALCHERINGA

Last appearance. Bedeva approximans, Polinices subvar&ns, Penion spatiosus, Phos gregsoni, Fusinus gippslandicus, Sydaphera wannonensis, Gemmaterebra subcatenifera, Costellaria euglypha, Micantapexpritchardi, Chlamys meringae, Cardita kalimnae, Neotrigonia acuticostata, Neotrigonia howitti. Restricted. Ctenocolpus pagodula, Hartungia dennanti, Mactra axiniformis.

Molluscan Assemblage X V I - - Jemmys Point Flinders This assemblage is based on the molluscan Molluscan Assemblage X V I I Island fauna in the Jemmys Point Formation cropping out in the road cutting on the This assemblage is based on the fauna in the Princes Highway at Jemmys Point, Cameron Inlet Formation cropping out in Kalimna, and in the cliff between the waterholes and drains on the east side of Kalimna Jetty and Jemmys Point. The fossil Flinders Island. Many of the waterholes, locality numbers are FL 148 and FL 149 which yielded rich molluscan faunas shortly respectively. The lithology is a fawn after excavation, probably will not continue calcareous silty sand in which the molluscs to yield material in the future; accordingly, are concentrated in bands of complete and the type locality chosen is the North broken shells. The stratigraphy at this site Patriarch Drain, east of the Link Road at has been discussed in detail by F. A. Memana. The lithology varies from a grey shelly sand through coquina to marl. The Singleton (1941) and Wilkins (1963). Superposition with respect to the stratigraphy of the formation has been preceding assemblage can be established discussed by Darragh & Kendrick (1971) and directly in the roadcutting on the Princes Sutherland & Kershaw (1971). Highway, northeastern side of Bunga Creek, Superposition with respect to the where the assemblage occurs in beds (d) to preceding assemblage can only be (h) of Wilkins (1963), 3.5 m above bed (b) in established indirectly by the occurrence of which Molluscan Assemblage XV occurs. living species in the assemblage not present The assemblage is of Early Pliocene age in Molluscan Assemblage XVI. and it is referred to Mallett's Zone V 14A. In The age of the assemblage is not known terms of the Australian stages, it is type with certainty but is probably Late Pliocene. Kalimnan. It cannot as yet be referred to a foraminiferal zonation, as no diagnostic Localities correlated with the type locality. FL 137, Forsyth's bank, Grange Burn; FL Foraminifera have been recorded from the 138, Grange Burn, rock stack; FL 139, Cameron Inlet Formation. There is no Australian Stage name McDonald's bank, Muddy Creek; FL 140, southeastern available for this part of the geological bed 6d, northeastern side, Bunga Creek; FL 141, southwestern side, Bunga Creek; FL column. No direct correlation with the 142, bed 6g, northeastern side, Bunga Creek; Yatalan stage of the St Vincent Basin, South FL 143, left bank, Nowa Nowa Arm, Lake Australia is possible as yet, because the term Tyers; FL 144, south side, Lake Tyers is based on an area in the Austral IndoAboriginal Reserve; FL 145, allot. 6, western Pacific Province. bank of Lake Tyers; FL 146, Lake Tyers, 1 Locafities correlated with the type locality. km northeast of Tyers House; FL 147, F7, Apart from numerous artificial exposures in Nyerimalang Jetty; FL 150, eastern side, the vicinity of the type locality, no other Hopkins Bight, Nungurner; FL 151, localities have yet been correlated with Nyerimalang Estates Road, right bank, certainty. It is possible that the road cutting Merringa Creek; FL 152, 100 m north of on Dutton Way, Portland, belongs here but bridge over Meringa Creek. the fauna from that locality is poor. Key genera and species. First appearance. Key genera and species. First appearance. Leiopyrga quadricingulata, Marginella cf. Ctenocolpus australis, Umbilia hesitata, formicula, Scaeoleda crassa, *Zenatina Polinices aulacoglossus, Mamilla melanovictoriae. stoma, Penion mandarinus, Penion maxi-

ALCHERINGA

mus, Neotrigonia margaritacea, Gari kenyonRtna, Placamen placidum. Last appearance. Leiopyrga quadricingulata, Tylospira coronata, Beltoliva nyrnphalis, Nannamoria paraboloides, Tucetona convexa, Proxichione moondarae. Restricted. Pelicaria gilli, A lcithoe (,4 lcithoe) orphanata, Nannamoria cinctuta, Miltha flindersiana, Tawera cf. spissa. Molluscan A ssem blage X VIII -- Lhnestone Creek This assemblage is based on the fauna in the shell beds at the base of the Werrikoo Limestone, cropping out in the valley of the Glenelg River between Roscoe's Cliff and Caldwell's Cliff near Dartmoor. The stratigraphy has been studied in some detail by several authors (O. P. Singleton et al., 1976 and references therein; Mallett, 1977). The lithology varies considerably from calcarenite to coquina and shelly quartz sand, indicating deposition in very shallow water. Outcrops containing a wide variety of molluscan species are difficult to locate, though individual species may be collected easily in their thousands. Superposition with respect to the previous assemblage can be demonstrated only indirectly by the occurrence of living species not present in Molluscan Assemblage XVII, and by the absence of other species found in the latter and the older Assemblage XVI. The top of the assemblage is defined by the entry of Pecten alba into the geological column which, for the purposes of this paper marks the beginning of the Pleistocene in accordance with the usage of Singleton et al. (1976). The age of this assemblage is probably Late Pliocene on the basis of correlation by Foraminifera (Singleton et al., 1976) and is referred to Mallett's Zone V 14 B. In terms of the Australian stages, it is type Werrikooian. Localities correlated with the type locality. Outcrops of the Memana Formation in waterholes north of Memana, Flinders Island. Key genera and species. First appearance. Notocypraea angustata, Sydaphera purpuriformis, Marginella johnstoni, Semicassis semigranosa, Glycymeris striatularis, Chlamys asperrimus, Ostrea angasi, Sunetta aliciae, Tawera gallinula, Katelysia peronii, Katelysia rhytiphora, Anapella cycladea.


107

Last appearance. Ennucula kalimnae, Scaeoleda killara, Limopsis werrikooensis.

Acknowledgements I wish to thank Owen P. Singleton, Alan Beu, Charles Fleming, George Kendrick, Phillip Maxwell, Cliff Mallett, Winston Ponder and Barry Wilson for assistance and encouragement at various stages of this work; Peter Jell and Owen P. Singleton for their constructive comments on the manuscript; Hilary Newton for assistance with Table 2; and Marilyn Hutchison for typing the manuscript.

REFERENCES AllELE. C., GLOE, C. S., Ho~'KINt.i.J.B., HOLDGAFE, G., LAWRENCE,G. R., RIPPER, D. & THRELFAEI., W. F., 1976. Tertiary. In Geology of Victoria, J. G. Douglas & J. A. Ferguson, eds, Spec. Publ. geol. Soc. Aust. 5, 177-274. BAKER, G., 1950. Geology and physiography of the Moonlight Head district, Victoria. Proc. R. Soc. Vict. 60, 17-43. BENNErr, 1. & POPE. E. C., 1953. Intertidal zonation of the exposed rocky shores of Victoria, together with a rearrangement of the biogeographical provinces of temperate Australian shores. Aust. J. mar. Freshwat. Res. 4, 105-159. BEU, A. G. & MAXWELL, P. A., 1968. Molluscan evidence for Tertiary sea temperatures in New Zealand: a reconsideration. Tuatara 16, 68-74. BLACKWELDER, B. W., 1981. Late Cenozoic stages and molluscan zones of the U.S. middle Atlantic Coastal Plain. Paleont. Soc. Mere. 12, 1-34. BROWN, D. A., CAMPBELL,K. W. S. & CROOK, K. A. W., 1968. The geological evolution o f Australia andNew Zealand. Pergamon, Oxford, 409 p. CARTER, A. N., 1958. Tertiary Foraminifera from the Aire District, Victoria. Bull. geol. Surv. Vict. 55, 1-76.

CARTER, A. N., 1964. Tertiary Foraminifera from Gippsland, Victoria, and their stratigraphical significance. Mem. geol. Surv. Vict. 23, 1-154. CHAPRONtERE, G, H., 1980. Influence of plate tectonics on the distribution of Late Paleogene to Early Neogene larger foraminiferids in the Australasian Region. Paleogeogr. PaleoclimatoL Paleoecol. 31, 299-317. CRESPIN, I., 1943. The stratigraphy of the Tertiary marine rocks in Gippsland, Victoria. Palaeont. Bull. Canberra 4, 1-101. CRESPIN, I., 1950. Australian Tertiary microfaunas and their relationships to assemblages elsewhere in the Pacific region. J. Paleont. 24, 421-429. DARRAGH, T. A., 1969. A Revision of the Family Columbariidae (Mollusca: Gastropoda). Proc. R. Soc. Vict. 83, 63-119.

108

T.A. DARRAGH

DARRAGH, T. A., 1970. Catalogue of Australian Tertiary Mollusca (except Chitons). Mere. natn. Mus. Vict. 31, 125-212. DARRAGH, T. A., 1971. Revision of the Australian Tertiary Volutidae (Mollusca: Gastropoda). 1. The subfamily Athletinae. J. malac. Soc. Aust. 2, 163185. DARRAGH, T. A. & KENDRICK, G. W., 1971. Zenatiopsis ultima sp. nov., terminal species of the Zenatiopsis lineage (Bivalvia: Mactridae). Proc. R. Soc. Vict. 84, 87-92, pl. 1. DORMAN, F. H., 1966. Australian Tertiary Paleotemperatures. J. Geol. 74, 49-61. EKMAN,S., 1953. Zoogeography o f the Sea. Sidgwick & Jackson, London, 417 p. FINLAY. H. J. & MARWICK,J., 1940. The divisions of the Upper Cretaceous and Tertiary in New Zealand. Trans. R. Soc. N.Z. 70, 77-135. FLEMING. C. A., 1967. Cenozoic History of the IndoPacific and other warm-water elements in the marine Mollusca of New Zealand. Venus 25, 105117. FLEMING, C. A., 1979. The geological history o f New Zealand and its life. Auckland University Press, Auckland, 141 p. GLENIE, R. C., 1971. Upper Cretaceous and Tertiary rock-stratigraphic units in the central Otway Basin. In the Otway Basin of South-Eastern Australia, H. Wopfner & J. G. Douglas, eds, Spec. Bull. geol. Survs S. Aust. & Vict., 193-215. GOSTIN, V. A., 1966. Tertiary stratigraphy of the Mornington District Victoria. Proc. R. Soc. Vict. 79, 459-512. HALL, T. S. & PRITCHARD, G. B., 1896. Remarks on the proposed subdivision of the Eocene Rocks o.f Victoria. Proc. R. Soc. Vict. 8, 151-168. HALL, T. S. & PRITCHARD, G. B., 1902. A suggested nomenclature for the marine Tertiary deposits of southern Australia. Proc. R. Soc. Vict. 14, 75-81. HEDLEV, C., 1902. Mollusca. Part 1. In Scientific results of the trawling expedition of H.M.C.S. 'Thetis', off the Coast of New South Wales in February and March, 1898. Mere. Aust. Mus. 4, 287-324. KNOX, G. A., 1980. Plate tectonics and the evolution of intertidal and shallow-water benthic biotic distribution patterns of the Southwest Pacific. Palaeogeogr. Palaeoclimatol. Palaeoecol. 31, 267297. LINDSAY, J. M., 1970. Melton Limestone: Multiple midTertiary transgressions, South-Eastern Gawler Platform. Q. geol. Notes geol. Surv. S. Aust. 33, 2-10. LOWRy, D. C., 1970. Geology of the Western Australian part of the Lucia Basin. Bull. geol. Surv. West. Aust. 122, 1-201. LUDBROOK, N. H., 1954. The molluscan fauna of the Ptiocene strata underlying the Adelaide Plains. Part 1. Trans. R. Soc. S. Aust. 77, 42-64. LUDBROOK, N. H., 1958. The stratigraphic sequence in the western portion of the Lucia Basin. J.R. Soc. West. Aust. 41, 108-114. LUDBROOK, N. H., 1959. A widespread Pliocene molluscan fauna with Anodontia in South Australia. Trans. R. Soc. S. Aust. 82, 219-223. LUDBROOK, N. H., 1969. The genus Miltha (Mollusca: Bivalvia) in the Australian Cainozoic. Trans. R. Soc. S. Aust. 93, 55-63. LUDaROOK, N. H., 1971. Large gastropods of the families Diastomatidae and Cerithiidae (Mollusca: Gastropoda) in Southern Australia. Trans. R. Soc. S. Aust. 95, 29-42. LUDBROOK,N . H., 1973. Distribution and stratigraphic

ALCHERINGA

utility of Cenozoic molluscan faunas in southern Australia. ScL Rep. Tohoku Univ. Second Series (Geology). Spec. Vol. 6, 241-261. LUDBROOK, N. H., 1978. Quaternary molluscs of the western part of the Lucia Basin. Bull. geol. Surv. W.A. 125, 1-286. MACUMBER, P. G., 1966. Completion Report, Waare No. 1. Rep. geol. Surv. Vict. 1967/46 (Unpubl.). MALLETT. C. W., 1977. Studies in Victorian Tertiary Foraminifera Neogene Planktonic Faunas. Unpubl. Ph.D Thesis, Univ. of Melbourne. McCoy, F., 1861. On the ancient and recent natural history of Victoria. In Catalogue o f the Victorian Exhibition 1861, with Prefatory Essays. Exhibition Commissioners, Melbourne, 131-145. McCoy, F., 1867. On the recent zoology and palaeontology of Victoria. Intercolonial Exhibition Essays 1866. Steam Printing Works, Melbourne, 1-24. McGoWrAN, B., 1978, Early Tertiary foraminiferal biostratigraphy in Southern Australia: a progress report. Bull. Bur. Miner. Resour. Geol. Geophys. Aust. 192, 83-95. RAGGATT, H. G. & CRESPIN, 1., 1955. Stratigraphy of Tertiary rocks between Torquay and Eastern View, Victoria. Proc. R. Soc. Vict. 67, 75-142. SCHELTEMA, R. S., 1971. Larval dispersal as a means of genetic exchange between geographically separated populations of shallow-water benthic marine gastropods. Biol. Bull. mar. Lab. Woods Hole 140, 284-322. SINGLETON, F. A., 1941. The Tertiary geology of Australia. Proc. R. Soc. Vict. 53, 1-125. SINGLETON, F. A., 1943. An Eocene molluscan fauna from Victoria. Proc. R. Soc. Vict. 55, 267-278. SINGLETON. O. P., 1965. Geology and Mineralisation of Victoria. In Geology o f Australian Ore Deposits, 2nd ed., McAndrew, J., ed., Australian Institute of Mining and Metallurgy, Melbourne, 440-449. SINGLETON, O. P., 1968. Otway Region. In A Regional Guide to Victorian Geology, Marsden, M. A. H., & J. McAndrew, eds, Melbourne University Geology Department, Melbourne, 117-131. (Originally issued in 1967 as a Handbook for Geology Excursions of the 39th ANZAAS Congress). SINGLETON, O. P., McDOUGALL, I. & MALLETT, C. W., 1976. The Pliocene-Pleistocene boundary in southeastern Australia. J. geol. Soc. A ust. 23, 299311. ~STIRTON, R. A., TEDFORD. R. H. & MILLER, A. H., 1961. Cenozoic stratigraphy and vertebrate paleontology of the Tirari Desert, South Australia. Rec. S. Aust. Mus. 14, 19-61. SUTHERLAND, F. L. • KERSHAW, R. C., 1971. The Cainozoic geology of Flinders Island, Bass Strait. Pap. Proc. R. Soc. Tasm. 105, 151-175. SYLVESTER-BRADLEY, P. C., 1971. Dynamic factors in animal palaeography. In Faunal Provinces in Space and Time, F. A. Middlemiss & P. F. Rawson, eds, Seel House Press, Liverpool, 1-18. TATE, R. ,~ DENNANT, J., 1893. Correlation of the marine Tertiaries of Australia. Part l, Victoria, with special notes on the Eocene beds at Spring Creek and at the mouth of the Gellibrand River. Trans. R. Soc. S. Aust. 17, 203-226. VALENTINE, J. W., 1961. Paleoecologic molluscan geography of the Californian Pleistocene. Univ. Calif. Pubis. geol. Sci. 34, 309-442. VALENTINE, J. W., 1967. The influence of climatic fluctuations on species diversity within the Tethyan Provincial System. In Aspects o f Tethyan

ALCHERINGA

Biogeography, C. G. Adams & D. V. Ager, eds, Systematics Association Publication 7, 153-166. Will.s, F. E., 1980. The distribution of shallow water marine prosobranch gastropod molluscs along the coastline of Western Australia. Veliger 22, 232247. WINZ. W., 1938-1944. Gastropods. Teil 1: Allgemeiner Teil und Prosobranchia (Amphigastropoda und Streptoneura). Handbuch der Paldozoologie 6, Borntraeger, Berlin, 1639 p.


109

WJtKINS, R. W. T., 1963. Relationships between the Mitchellian, Cheltenhamian and Kalimnan Stages in the Australian Tertiary. Proc. R; Soc. Vict. 76, 39-59. WILSON, B. R., 1971. lnAustralian Shells, B. R. Wilson & K. Gillett, Reed, Sydney, Melbourne, 168 p. ZINSMt:IsrER, W. J., 1982. Late Cretaceous-Early Tertiary molluscan biogeography of the SouthernCircum-Pacific. J. Paleont, 56, 84-102.

110

T.A. D A R R A G H

A LCHERINGA

3 Species

Species

Gastropoda Albany

Cellana j u tsoni Bosillissa cossmanni

x

Aslraea hudsoniana

x

Bobna flindersi darraghi

x

x

Collonista otwayensis Crosseola princeps Spirocolpus aldingae

x

x

x

x

x

×

Pterochelus adelaidensis

x x

Pterochelus manubrialus

x

x

x

x

x

Anguillospira adelaidensis

x

Trophon Iorquatus

×

x

x

x

Enatimene monotropis

x

x

x

Gemmixystus icosiphyllus

x

x

Cominella pumila

x

x

Cominella pertusa

×

x

Dennantia aldingensis

x

x

x

Austrolithes incompositus

×

x

x

x

Jetwoodsia nullarborica

x ×

?

Orthochetus pagoda Notacirsa lampra l~nctiscala Ioxopleura

x

Cirsotremapleiophylla

x

x

x

x

× x

Microcolus actinostephes

x x

×

Fusinus sculptilis

x

x

Tectifusus tholoides

x

x

×

x

x

Niso kimberi

x

Margineulimo danae

x 9.

×

x

x

×

x

x

Ancillistasubgradata

×

Gracilispira ligata

x

Mitraria varicosa

x

Microvoluta subcrenularis

x

Micro valuta complanata

x

Sirius fenestratus

x

Athleta (Ternivoluta) curvicostata

Sirius in terlineatus

x

Mitreola salaputium

Sirius tabulatus

X

Alcithae (Waihaoia) pagodoides

Sirius triplicatus

X

Notopeplum protorh y s u m

Sirius anguliferus

x

Notopeplum primarugatum

Capulus circinatus

x

Scaphella j o h a n n a e

Calyptropsis arachnoideus

x

x

Notovoluta capitonica

Calyptrea plaeuna

x

x

Notovoluta variculifera

Proterato australis

X

x

Arehierato pyrulata

x

x

Semitrivia p o m p h o l u g o t a

X

X

Ellatrivia m i n i m a torquayensis

x x

Cypraedia clathrata

X x

x × x

x

x

x

x x

x x

x

x

x x

x

×

x x

x x x

X

Inglisella turriculata

x x

x

x

x

x

cf

x

x x ?

x

x

cf

Friginatica aldingensis

×

x

x

x

x

x

x

x

'Austrosassia ' cribrosa

X

X

X

X

Ratifusus n odulatus

x

Semitriton dennanti

x

Marginella malla

x

x

x

Marginella regula

x

x

x

x

Marginella aldingae

x

x

Marginella kitsoni

x

Vexithara citharelloides

x

Vexithara pumila

X

x x

x

x

Marginella palla

Cam#as aldingensis

x

x

x

x

x

cf

x

x

x X

x

Comitas cudmorei

x

Columbarium calearatum

x x

x

x

x

x

×

Mikiyamaia victoriae

X x

x

x

A p i o t o m a wilkinsoni ?

×

×

A p i o t o m a bassi

x

Marshallaria otwayensis

x

Paramarshallena propebelloides

Table 1. Mollusca from Late Eocene and Early Oligocene localities of southern Australia.

x x

x

x

x

x '

x

x

Siratus tenuicornis

x x ×

Semitriton varicosum

Ampullina e l f usa

x

x

x

x

x

x

Oamaruia ptychotropis

×

Murexsul sublaevis

x x ?

Anapepla micra

x

x

x

x

x

x

x

x

x

x

x

x

x

x

Laevityphis ludbrookae

x

X

x

Murexsul prionotus

x

x

x

Tanea windei

x x

X

Atlanta fossilis

Cotumbarium cochleatum

x

Alcizhoe (Waihaoia) cribrosu

cf

x

x

x x

x

Sassia oligostira

x

Tectifusus aldingensis Gemmoliva adelaidae

Sirius costatus

Sirius subquadratus

x

cf

Microcolus apiciliratus

×

x

x

x

x

Cirsotrema mariae

x x

x

x

Tritonalia tridentata

Lilax actinotus

x

x x

x

x ×

Trophon h ypsellus

×

Heliacus (Torinista) darraghi

x x

x

Heliacus (A warua) o t w a y a n u s

Willungia ovulatella

x x

9.

(= Spirocolpus pritchardi) Pareora stylacris

Ataxocerithium eoncatenatum

×

Pteropurpura b i f rons

Pterochelus otwayensis

X

Munditia lamellosa

Pteropurpura calva

X X X X


ALCHERINGA

111

o

o
olinices subvarians ~ustrotriton bassi ~ustrotriton garrardi edeva ~edeva approximans ~os gregsoni Bello/iva nympha/is

Table 2 (cont.). Ranges of key taxa in molluscan assemblages.

115

116

T.A. DARRAGH

X I V Rose Hill

Alocospira A/ocospira orycta Amoria undulata Tucetona convexa /Veotrigoniahowltti Placamen P/acamensubroboratum Bassinapaucirugata Nannamoria paraboloides Micantapex pritchardi Tylospira Tylospira clathrata Eucrassetellaro$icollina X V Bunga Creek

Tylospira coronata Nassariu$crassigranosus Penion spatiosu$ Fu$inu$gippslandicu$ Costellaria euglypha Ericuse $owerbyi Sydapherawannonensis Gemmaterebra$ubcatenifera Ennucula kalimnae Chlamys meringae Cardita kalimnae Tylospira lirata Athleta (Ternivoluta) bungae Eucrassate/ladorsennata XVI Jemmys Point

Leiopyrga quadricingulata Marginella cf. formicula Scaeoledacrassa Zenatina Zenatina victoriae Ctenocolpuspagodu/a Hartungia dennanti Sfactraaxiniformi$ XVII Flinders Is.

Ctenocolpusaustralis Umbilia hesitata Mamil/a melanostoma Polinicesaulacog/o$$u$ Penlon mandarinu$ Penion maximus ~ellicaria gilli Alcithoe (Alcithoe) orphanata Nannamoria cinctuta Miltha f/indersiana Tawera cf spissa Neotrigonia margaritacea Placamenplacidum Gari kenyoniana XVll[ Limestone Creek

Notocypraea angustata Semicassissernigranosa Syd=pherapurpuriformi$ Marginel/aiohnstoni Glycymeris striatu/ari$ ~ * ~ =ngasi Chlarnys asperrimus Sunetra aliciae Tavveraga/linula Katelysla peronii Katelysia rhytiphora Anapella cycladea Sco¢=oledaki/lara Limopsis werrikooensi$

Table 2 (cont.). Ranges of key taxa in molluscan assemblages.

ALCHERINGA