Sea Temperatures in New Zealand During the Cenozoic Era, as Indicated by Molluscs

A. G. Beu,

Geology Department, Victoria University of Wellington. [Received by Editor, 23 September 1965.]

Abstract

Time ranges of New Zealand Tertiary molluscan genera now living only in seas warmer than those of New Zealand are plotted on a table of New Zealand stages. On a more detailed table occurrences of Lower Pleistocene warm- and cold-water genera and species are plotted. A graph of temperatures has been constructed from the tables. New Zealand was marginally tropical in Lower Miocene times, subtropical for most of the rest of the Tertiary, and warm-temperate during Pliocene times. It fluctuated between temperate and subantarctic during the Quaternary Period.

Introduction

Many workers on New Zealand Cenozoic molluscs have commented on the warmwater faunas occurring in the middle Tertiary. Fleming (1944: 207) gave references to some of these publications. Workers on echinoids (Fell, 1954) and corals (Squires, 1956; 1958) have also mentioned evidence for warm conditions during middle Tertiary times and have attempted to estimate relative or absolute temperatures.

All these workers thought the fauna at Pakaurangi Point, Kaipara Harbour, to be of Altonian age, but this fauna is now considered to be Otaian on the evidence of Foraminifera (Thompson, 1961; Scott, 1965). At Pakaurangi occur the warmest known elements in our fauna, and the incorrect age ascribed to it has made previous graphs look more complicated than necessary. For this paper I have attempted to summarise the ranges of all useful temperature-index molluscs in the New Zealand Cenozoic in the light of the ages we now give to important strata.

Estimates of temperatures have been made on two scales. In Table I the known ranges in the New Zealand Cenozoic of warm-water molluscan genera now living outside New Zealand have been plotted, enabling a broad estimate to be made of Tertiary sea temperatures. Usually only complete ranges are shown on this table, and only a few absences are shown (by dotted lines), where they are considered to be significant because of long duration or possible temperature implications.

In Table II the known ranges in the late Cenozoic (Upper Pliocene and Lower Pleistocene) of New Zealand of living warm- and cold-water species and genera have been plotted, and records from Upper Pleistocene (Hawera Series) faunas have been included, although these are mostly interglacial and are adequate for littoral forms only. This table enables a more detailed estimate of temperature fluctuations during New Zealand Lower Pleistocene times. Following Vella's (1963) work on cyclothems, the temperatures indicated by Pleistocene Mollusca are taken as representing interglacial periods, rather than glacials and interglacials as suggested by Fleming (1953: 301). The unconformities between cyclothems are taken to represent glaciations, i.e., periods of low sea level with no deposition, and the strata themselves to indicate interglacial periods, i.e., periods of high sea level with deposition.

In all cases ranges have been determined as accurately as possible from specimens in the collection of the New Zealand Geological Survey, with the help of Dr C. A. Fleming and Mr P. A. Maxwell. To begin with, a chart was made from the faunal compilations in the definitions of New Zealand's stages by Finlay and Marwick (1940; 1947), and from the faunal history given in Fleming's paper on New Zealand biogeography (Fleming, 1962 a). Many other records have been added from papers by Powell, Laws, and other workers. Previously published ranges of many genera are greatly extended in Tables I and 11, but they probably are still incomplete; the conclusions presented may have to be substantially altered when more specimens have been collected,

Constitution and Origin of Successive Faunas (Tables I, II)

Wangaloan

The Wangaloan Stage (probably = Teurian) contains a rich molluscan fauna, but most genera are endemic and extinct. The primitive Struthiolariid Perissodonta lives in polar waters today, and the several members of the family Aporrhaidae are restricted to temperate and subpolar regions. Perissodonta was rather more widespread, and Aporrhaidae were much more so during the Eocene and the living representatives seem to be reduced remnants. Their presence at Wangaloa is thought not to indicate cold conditions. The presence of four genera now living in the Indo-Pacific, Pteria, Cucullaea, Miltha, and Polinices, and of Proficus, Priscoficus, and Tudiclana, extinct genera with warm-water relatives, suggests that this fauna was subtropical.

Waipawan to Porangan

Over most of New Zealand the sediments of the Waipawan to Porangan ages are probably of abyssal facies and lack macrofossils. Poorly dated faunas from

the eastern part of the South Island, such as those from Otaio Gorge, South Canterbury, and from the Kauru Formation of Oamaru, probably represent part of this time and are very similar to that at Wangaloa. One record of the Harpid genus Eocithara in the Mangaorapan is of interest—the family is now almost entirely tropical, but one species of Austroharpa lives in South Australia, and the family is probably now more restricted in distribution than it once was. The only other New Zealand Harpid is Marwickara, an endemic subgenus of Eocithara, known from the Bortonian and Duntroonian stages. It seems that New Zealand was subtropical from Waipawan to Duntroonian times.

Bortonian

In the Bortonian Stage appear the earliest representatives of several genera which are wide-ranging today, and were characteristic of New Zealand for much of the Tertiary period. They include Austrosassia, now occurring rarely in the southern Pacific and as far south as Farewell Spit in New Zealand. Genera now widespread in the Indo-Pacific, and in most cases in other warm seas as well, include Marshallena (oral comm., Dr A. W. B. Powell), Gemmula, Placamen, Plicatula, Area, Sinum, large Conus 5.1., Ficus, and Cypraea (as various sub-genera such as Eocypraea and Bernayea) . Extinct forms of probable warm-water relationships include Clijdenia (later to be our largest Mitrid), Falsicolus, and the Nautiloid Aturia.

Kaiatan

In the Kaiatan Stage many important genera first appear. Isognomon, Cheilea, and Hinnites lived in New Zealand for much of the Tertiary and are now fairly wide-ranging in most warm seas. The common New Zealand genus Conilithes (better known as Conospirus) is first known in the Kaiatan Stage. Small Triviids (ribbed cowries) of various genera also appear first in the Kaiatan. An interesting discovery by the New Zealand Geological Survey is the tropical genus Colubraria, known from new species in each of the Kaiatan and Waitakian Stages, in the Awamoan or Altonian of Parengarenga Harbour, Northland, and in the Clifdenian Stage at Clifden. Other Kaiatan genera largely restricted to very warm water today are Arcopsis (also known as Fossularca) , Neverita, Distorsio (as the extinct subgenus Personella), and Uxia. The extinct Nautiloid Eutrephoceras was probably a warm-water form, and is known in New Zealand from the Kaiatan and the Upper Cretaceous. The squat flat-topped cone-shell Parviconus first occurs in the Kaiatan, is known also from the Otaian, and now lives as far south as Tasmania. As only two definitely tropical genera are known, it seems unlikely that the Kaiatan sea was truly tropical.

Runangan

Only two warm-water arrivals are known in the Runangan Stage, probably because faunas are poorly represented. The peculiar " watering-pot" shell Clavagella appeared at this time, lasted until the Tongaporutuan in New Zealand, and still lives in very warm seas today. The Trochid gastropod Olivia (== Danilia) is known only from beds of Runangan age. The Runangan molluscan fauna at Trig. M, Totara, Oamaru, is very similar to Kaiatan faunas.

Whaingaroan

In the Whaingaroan Stage the common lamellibranch Eumarcia first appears, along with Pterynotus, which lasted sporadically until the present day in New Zealand and is now best developed in tropical seas. The genus apparently was

not living here in Hautawan times, but again invaded New Zealand in Nukumaruan times and now lives in Cook Strait (Dell and Fleming, 1964). Other important warm-water genera which had short ranges in New Zealand are true Lithophaga, known only from the Whaingaroan Stage, and the " thorny oyster" Spondylus, known from the Whaingaroan and Otaian Stages in Northland.

Duntroonian

A group of new arrivals in the Duntroonian Stage includes the tropical and sub-tropical mud-flat dweller Pyrazus and several genera such as Amygdalum, Solecurtus, and Bathytoma, which, though short-ranging in New Zealand, are now fairly common in warm seas all around the world. The most interesting arrival in this stage is Maoricardium, which was originally described from New Zealand. A species recently recognised as Maoricardium is widespread in the western Indian Ocean (pers. comm., Dr A. M. Keen to Dr C. A. Fleming) and closely resembles the huge M. spatiosum, which lived in New Zealand during the Miocene and Pliocene. The large Gancellariids Maorivetia and " Trigonostoma " were probably warm-water genera.

Waitakian

Arrivals recorded in the Waitakian Stage are Eucrassatella, Chama, Trichomya, and Guildfordia (subgenus Pseudastralium) . The large Lamellibranch Eucrassatella lived on until the Waipipian Age in New Zealand and now lives from Tasmania to Northern Australia. Chama now lives in Tasmania but is more characteristic of warmer seas. Trichomya, common in the Indo-Pacific, is represented by sporadic specimens from the Waitakian to Altonian Stages. Particularly interesting is the occurrence of Guildfordia {Pseudastralium) (= Astraea n.sp. of Fleming, 1955: 1054) in the Waitakian and Kapitean Stages, for it now lives only in southern Japan.

Otaian

The Pakaurangi Point fauna and those from other important localities in the Waitemata Formation in Auckland and Northland are now thought to be of Otaian age rather than Altonian. This puts back the peak on all previously published temperature graphs. We now know that the Otaian Stage contains several tropical genera of molluscs, larger Foraminifera, and reef corals, and this fauna is definitely tropical. The molluscan fauna at Pakaurangi is not typical of New Zealand, for while common New Zealand genera such as Neocola still occur they are nearly all represented by rather peculiar species, and members of the characteristic New Zealand family Struthiolariidae are rare. The warm-water genera Murex, Merica, Hyphantosoma, Siratus, Oniscidea, and Septifer appear for the first time and in general are short-ranging in New Zealand after the Otaian, and the warm-temperate to tropical genus Eudolium is known only from Pakaurangi Point. The strictly tropical coral-inhabiting gastropod Coralliophila is rare at Pakaurangi Point, and is also known from one record from the Clifdenian strata of Westland. The tropical rock-borer Parapholas (Powell, 1938) is known only from Waiheke Island (where Struthiolaria is common), and the warm-tem-perate to tropical genera Lutraria and Bembicium appear at Waiheke and are rather sporadic through the rest of the New Zealand Tertiary. The assemblage is by far the warmest known in New Zealand, but tropical genera are not abundant and the central tropical ornate Cymatiids, Gypraeids, Harpids, and Strombids are not known. Strombidae do not appear to have radiated until the Pliocene (Abbot, 1960), so that their absence is not surprising, but the absence of the other forms and the occurrence of a few worn specimens of hermatypic corals indicate that

conditions can only have been marginally tropical. Hermatypic corals have been found in the Otaian strata near Hick's Bay, East Cape, and it seems likely that the 70°F. isotherm, a convenient biological boundary for the tropical zone, lay across New Zealand in about the vicinity of Rotorua during Otaian time.

Post-Otaian

Few warm-water genera of molluscs reached New Zealand after the Otaian Age. Cymatiella is known in New Zealand from a common Awamoan form and a probable Opoitian specimen, and is now a common littoral form of Tasmania and southern Australia. Cronia and Aphera, restricted to the Awamoan Stage in New Zealand, are widespread but rather rare in tropical to subtropical seas at present. The Thaid Cronia was compared by its author to a form living now around Sydney. The strongly sculptured Volute genus Lyria occurs in the Southland Series. Most present day species of Lyria are tropical, but one lives in South Australia and the genus is thus somewhat eurythermal. Olivella, which seems to have appeared here in the Lillburnian Age, is at present very widespread in warm to tropical seas around the world, as is Trachycardium, of which an endemic subgenus Ovicardium occurs from the Kapitean to Waitotaran stages. The genus Patro, arriving in the Waipipian Age, occurs in New South Wales today. None of the Post-Otaian arrivals are particularly stenothermal warm-water genera. Many of the genera recorded on Table I died out in the Southland and Taranaki Epochs, and scarcely any were able to survive the first glaciation. The genera Sinum, Merica, Marshallena, and Eucrassatella became extinct in New Zealand at the end of the Waipipian Age, and Miltha, Polinices, Olivella, Maoricardium and Trachycardium died out at the end of the Waitotaran (end of the Tertiary).

Upper Pliocene to Recent

Table II shows the detailed history of warm- and cold-water genera and species in the New Zealand Upper Pliocene to Recent. It shows that four warmwater genera lived through the Hautawan in Wanganui district, while, within the time range of this table, the warm-water genus Chama is known only in the Hautawan. Xenophalium (Xenogalea) first appears in the Hautawan (undescribed new species in the New Zealand Geological Survey, from Wairarapa) but as this now lives at Stewart Island it must be regarded as a eurythermal genus. Other than these, the species that characterise the Hautawan strata of Wairarapa and North Canterbury are now living off Otago Peninsula and farther south. These include Chlamys (Zygochlamys) delicatula, Calliostoma couperi (aff. spectabile, Auckland Islands, and foveauxana, Foveaux Strait), Zeacolpus (Stiracolpus) symmetricus and Cominella (Eucominia) nassoides otakauica (Fleming, 1944: 209 et seq.). Extensive shellbeds with abundant Chlamys delicatula in South Wairarapa leave little doubt that the subantarctic convergence lay well to the north of that area in the Hautawan Age, and the continuance of Isognomon, Eumarcia, Glycymeris s.s., and Patro in Wanganui (Fleming, 1953) suggests that the subantarctic convergence lay south of that area. Temperature fluctuations are suggested by the occurrence of microeyclothems in Wairarapa and of Chlamys delicatula in the Hautawa Shellbed in Wanganui (Fleming, 1953), and these probably explain some of the apparent temperature anomalies. Others could be explained by changes in ocean currents and in the paleogeography of the time (Fleming, 1962 a).

The Nukumaruan Stage contains the same four genera, Isognomon, Eumarcia, Glycymeris s.s., and Patro, together with Lutraria and Area, which both lived in New Zealand during Tertiary times but are not known in the Hautawan, and the

new arrivals Ellatrivia zelandica, Leucotina ambigua (Fleming, 1953), and a subspecies of Pterynotus angasi (Fleming, 1962 b: 115). It seems that the Nukumaruan represents a very warm interglacial period.

The only new arrivals in the Okehuan Stage are Acrilloscala, known from an undescribed species from the Ototoka Siltstone Tongue at Castlecliff (Fleming, 1953), and Cabestana spengleri. Xenophalium, Leucotina, and Pterynotus continue from earlier stages, and the temperature may have been about the same as today or a little warmer.

The most notable arrival in the Castlecliffian Stage is Pecten s.s. (Fleming, 1957), and others include Cabestana (waterhousei) debilior. A number of forms in the uppermost Castlecliffian at Wanganui and at Cape Runaway seem to be new arrivals of genuine Australian origin. These include Anadara, Capulus, Eunaticina, Nassarius, Austrosassia parkinsonia, Cabestana waterhousei cf. segregata, Charonia, Monoplex, Tonna, Heliacus, and Agnewia (Fleming, 1953; Powell, 1934). Of these Capulus and Eunaticina are known only in the Castlecliffian, Anadara became extinct in New Zealand before the end of the Pleistocene, and the rest still live in Northland. Temperatures varied throughout the Castlecliffian Age, as shown by the migration of forms of Pecten (Fleming, 1957), Pelicaria, and Stiracolpus (Marwick, 1957) at Castlecliff and reached a peak appreciably warmer than the present-day in late Castlecliffian times.

The few known Upper Pleistocene (Hawera Series) faunas are almost identical with Recent ones, the only extinct forms being Pecten benedictus zeehanae, Anadara trapezia, Leucotina ambigua, and Protothaca n.sp. (Fleming, 1953). In the Holocene, temperatures rose until the thermal maximum, then cooled again. They are generally considered to have risen again slightly during the last 100 years (e.g., causing the retreat of glaciers) and evidence for this is to be found in the continuing arrival in New Zealand of southern Pacific molluscs. The most notable recent discoveries in Northland are of specimens of the cowry Erosaria cernica tomlini, the Frog Shell Annaperenna verrucosa and the wentletrap Pomiscala perplexa (Powell, 1965). The cowries Erosaria cernica tomlini and Mistaponda vitellus have now been found alive at the Poor Knights Islands (Dr A. W. B. Powell, in litt.).

The Influence of Facies

Temperature decreases with increasing depth in the sea, so that increase in depth has the same effect on a fauna (broadly speaking) as does increasing distance from the equator. I have therefore tried to use the shallowest available facies for this summary. For many stages (line dotted on graph) the faunas or facies are inadequate. Differences in the molluscan faunas in the Otaian Stage of Pakaurangi Point, Auckland, and Bluecliffs, South Canterbury, could possibly be attributed solely to differences in depth of deposition, but differences in the planktonic Foraminifera suggest distinct latitudinal differences in surface-water temperatures during the Otaian (P. Vella, oral comm.).

The lack of a good Tertiary succession in Northland means that we shall never really be sure at what part of the Tertiary temperatures reached their peak in New Zealand. The occurrences of Spondylus in a Whaingaroan limestone near Whangarei Heads, of Coralliophila in the Clifdenian of Westland, and of hermatypic corals in probable Awamoan rocks at Motutara, Auckland, suggest that temperatures may actually have been tropical in New Zealand from about the Kaiatan to the Clifdenian, and that it is the lack of preservation of suitable facies that has removed most of the evidence of this.

The sea temperatures in which genera lived in the past have been taken to be similar to those in which they now exist. Such assumptions are the fundamental basis of direct interpretative paleoecology, and in general they seem to have a sound basis. However, it should be noted that the temperature requirements for a genus can change and undoubtedly have done so in the past in some cases.

The Temperature Graph (Fig. 1)

In spite of the above reservations, a graph has been constructed showing relative temperature changes in New Zealand during the Cenozoic Era (Fig. 1). It must be stressed that this is a highly subjective interpretation of the tables. It does not allow for variation in temperature over the country during each age. The graph indicates that New Zealand was subtropical for most of the Cenozoic Era, and that temperatures rose gradually during the early part of the era to become marginally tropical during the Waitakian and Otaian ages (early Miocene), then fell to become warm-temperate by the Opoitian Age (early Pliocene). An abrupt decrease in temperature at the end of the Waitotaran has been interpreted as indicating the beginning of the Pleistocene, and since that time temperatures have fluctuated mostly between cool and warm-temper-ate. During much of the Hautawan Age (early Pleistocene) they were cooltemperate to subantarctic. The history of the New Zealand Lower Pleistocene seems to have been more complicated than and fundamentally different from that of the Tertiary, but this may be due to inaccuracies in the estimates of Tertiary temperature. The pattern of temperature changes in the Pleistocene Period might be expected to arise gradually, and the Waitotaran cyclothem in Wairarapa and Hawke's Bay may be explained by some Pliocene fluctuation in temperature — probably not a glaciation in regions now temperate, but possibly a fluctuation of polar caps leading up to the Pleistocene glaciations. A suitable mechanism has been suggested by Wilson (1964).

The position of the temperature peak may be contrasted with that suggested by North American workers. Durham (1950) concluded from work on molluscs of the Pacific coast of the United States that the Eocene was the warmest period and that temperatures fell gradually throughout the rest of the Cenozoic. Durham later (1952; 1959) reached the same conclusion about the whole world and thought that temperatures were tropical all over the world in the Eocene, including during the Bortonian and " Tahuian" (approximately equivalent to Kaiatan) ages in New Zealand. This conclusion about New Zealand cannot be upheld, and the conclusion about temperatures all over the world is not in agreement with that reached about New Zealand in this paper. The contrasting conclusions can only be reconciled if either (a) the temperatures do not reflect changes in the solar radiation retained by the earth, or (b) New Zealand early Tertiary temperatures have been underestimated due to lack of suitable shallow-water faunas. The second alternative seems more likely than the first.

Confirmation of the graph presented here is given by Dorman and Gill (1959). These authors give a graph constructed from temperatures determined by oxygen isotope measurements on Australian macrofossils, and this graph is broadly similar to the one shown here.

Judged by their relationships and the fact that their occurrences fluctuated in sympathy with those of forms that now live in warm water, or in sympathy with the temperature graph, many endemic New Zealand lower and middle Tertiary molluscs must have been stenothermal warm-water forms. These include Hedecardium, Proxicharonia, Mauicassis, Incilaster, Opella, Tatara, Tropicolpus, Callusaria, Latirigona, Zeacuminia, and many of the large Pectinids, Venerids, Naticids, and Volutids.

Conclusions

1. All estimates of New Zealand Tertiary sea temperatures must be somewhat tentative because of the scarcity of shallow fades and the high endemism of early Tertiary faunas. The accuracy of estimation decreases rapidly backwards through time.

2. Allowing for (1), the graph of temperatures seems to have risen and fallen smoothly through the Tertiary, but to have oscillated strongly through the Pleistocene. Temperatures were subtropical through most of the Tertiary, marginally tropical during the early Miocene, and largely temperate since the Miocene. This contrasts with temperatures suggested by North American workers.

3. Many endemic New Zealand Tertiary genera were stenothermal warm-water forms.

Acknowledgments

I am greatly indebted to Dr G. A. Fleming and Mr P. A. Maxwell of the New Zealand Geological Survey for a number of unpublished generic records from Survey collections (Plicatula, Placamen, Clavagella, Personella, Colubraria, Parviconus, Murex s.s., and Siratus), for details of the ranges of many genera, and for extensive comments on the manuscript, and to Dr P. P. Vella, of the Geology Department, Victoria University of Wellington, and Dr R. K. Dell, of the Dominion Museum, for careful revisions of the manuscript. Mr E. F. Hardy draughted the tables and graph.

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A. G. Beu, Geology Department, Victoria University of Wellington, P.O. Box 196, Wellington.

GENUS | Wangaloan 3 <n TS Q § I 3 3 | | | | | CD Q 0 O 1 Q C 5’ 3 <3 3 | Kaiatan | Runangan Q | 3 1 | Porangan | Bortonlan 7S a a a Q 7T 3 o’ | Runangan zr a 3* lO a 3 1 Otaian 1 Awamoan | Altonian 8 I | LiMburnian Q o’! c Q 3 3 | [ | I Opoitian 1 1 I > ? Q 3 o o a a [ Altonian | Clifdenian | Lillburnian c q’ c Q 3 H o 3 (O Q -D o a 3 | Hautawan c I 1 Okehuan Q I 70 m o m z —I 3 | Ka pi teem I Opoitian I Walpipian 1 Waitotaran 1 Hautawan I Nukumaruan 1 Okehuan 1 Castlecliffian ! RECENT Z z r _ _ F. __ _ - r _ _ Z Cucullaea *™“ “* 1 “■ ““ - * “ — — ” E “ aa E E u __ _ _ — — — — Ln ! “ p p ” 0 p p p p p _ _ Miltha p an — an mm — r pj W w awn —i WI E ns ■™ E a? hta E sam 1 p p p P 0 p p p p p p p p P _ Polinices tmm —i — «■ — — “ — M — e — — E — MH a” ■■ aa mm i p p p “ p p p p p p p p p P _ Pteria — — — ■■ — 1— — mu — — p P — 0 — p _ Priscoficus — — — — -» — r « Proficus ns z Z Tudiclana »«■ L —i Eocithara — — p - - — — — — — — — — — t — — — — — — — ! -3 — — m — Area s. s. — — — — 1 — — - — , - - -j - 3 — - E E — — _ — —■ I p una p « ta i - — *"*T 3 Luiij - — aa ___ ri __ Sinum w ion w» ns sn “■ —= pa ip ■■ — E p BKM p — 1 p p p “ — Marshallena m tp 0 0 E P E P “ p p — E E N — “ — i p 0 — p p p p ■ Gemmula 0 0 ■n ra p w — E E _ E E W p — E i — 0 — ss — ■“ Conus s. 1. (except Parviconus & Conilithes) 1 r r~ r~ —— L__ HWM —j z~ z lZI L_ n ___ *ub mm __ IMA. 1 — r „ I "• LZ mm zz L_ — {— : Falsicolus 0 — p- — — — p — P i p p p p n — — E h r — E “ — — “ - — - - — — — - — Architectonica s. 1. mm 0 0 0 ns — 0 — n ; — — ss sn J Aturia •n — 0 0 — 0 — — 0 — — p p P —: — — — - - I r I i - _ — E | E *- — - — - - - — Z H — Cypraea s. 1. — 0 0 0 — p — P p - _ _ _ _ _ Clifdenia — — — — — — _ 0 E Z p* E 0 — — — E P p P P p Ficus e> 1— E mm — 0 — & aa 0 E nn L — P sn ns sn Placemen 0 hj Z z. P — _» — Z'P p ' Plicatula mm r ” z I — — i_ z Marwickara • Li t P ' [T tj 0 r r Isognomon ri «; lan - ! i — _ — — 0 F ■ ~ — MM P an P — p — P — — P “ Pj — p — P p p p p p — — — z — — — — P — — LrieiLea Hinnites — — — — — — — — — — E 0 H E — —J — — — L- — — ■— 1 — — — — ~ — Con Uithes (= Conospirus ) E E u _ 0 e 0 >»> 0 n __ ns Trivia s. 1. E E e Z e 0 . 0 _ £ a s m „ . n „ m M n m — — n m „ Colubraria 0 ~ — T aa. 0 E z 0 n _ Uxia X 1 1 __ _ _ 0 Z p z r E — z z Parviconus i — ... -t — I 1 — inn """ USB ha p ■saa ** Arcopsis (= Fossularca) 0 z n □ Neverita X H mm z Z n z Eutrephoceras □ z z t r z Distorsio (Personalia) X t s L i mm L_ i_ z Z z Clavagella X r E — E 3 3 — — — — P — — «_ — — — — — — — — Olivia (- Danilia) bn l_ J LJ U L □ Pteryn -us 1 B i — P P p P P p P ■n P n — P p _ W an ““ “ — “ “ a E “ -a Eumarcia s. 1. ■■ — w — — — — — — — — w» am ! — ss — —i P — — ““ — — — p Lithophaga Hi ■■■ E z U — Spondylus P“ — Amygdalum ■ i — CPP pi " Mli — m — 1 — I , — — — — — — — ___ __ — — 1 ■n — — — — z — —i z — “f— — Glycymeris s. s. p 1 p P p P p pi P p P — p _ Maoricardium p p P — P p p P p P _ Bathytoma — — I — — — — I I | E — - — E E — E E E p z — — — — p ns - ■SI ns p p Solecurtus X - p — Z — — — — Z — — — — _ ■>3 Maorivetia X ■» -o — p E Maorivetia X — — — — — — — — — ■— — — — — Z n ■a m p — — — — — — — - — — — — — — — — — - — Pyrazus X “Trigonostoma” X — — — — — — — — z - — 0 z R — — — — — 1 - — — z z z I — r~ — I — _ I Chama z L 3 “ E — ■ — — — — E _ L £! Eucrassatella | p P p p P p “ p P P “ Eucrassatella L H — H> H ; 1 E H — — -■ — h H aa H sn p p P P Guildfordia ( Pseudastralium ) X i M z Zj , L E — —| — E — — E I — i Trichomya □ __ __ Z E 0 _ __ - 0 _ “ p _ 3 _ J — U . _ _

STAGE GENUS Q a Q \STAGE 8 Q 3 to Q § 3 Q j Q | Mangaorapan I Heretaunqan I Porangan CP ! o o S 3^ Q 5’ 3 3 | Mangaorapan | Kaiatan I 73 | c | Bortonian 3 7S Q 5’ Q Q 3 ! 3 to | | a 3* n Q 3 i | Whaingaroan I Duntroonian I Waitakian | Otaian I Awamonn 1 Altonian | Clifdenian I Lillburnian | Waiauan 1 Tonqaporutuan 1 Kapitean | Opoitian | Waipipian f o a a 3 X Q Q * a 3 i| cf E) a c o 3 O <T 3r Q 3 I Castlecliffian I RECENT 3 | Duntroonian I Waltakian | Otaian > Q 3 o 3 3 1 Altonian | Clifdenian I Lillburnian I Waiauan 1 Tonqaporutuan 1 Kapitean | Opoitlan | Waipipian i o Q a 3 | Hautawan Z c c 3 Q C Q 3 | Okehuan ! I Castlecllffian ! 1 RECENT Lutraria M- ■ ■ ■ ■ ■ H ■ ■■ — •B i Meric a x ~~ mrm mu __ __ Bembicium X w n ■ E m ■ _ Hyphantosoma X WB m mm — — — — Oniscidia x I — — — — a a 3S “ — — — — — — — — — Siratus * Coralliophila 0 — z — — — — — — — — a m ■ ■ - — — — — — “ “ I I Septifer X X 0 m ■ ■ — _J m - ■ m " _P_ m M ■ — Pedicularia _ - » - ■ ■ m ■ " * ■ ** “ ■ Murex s. s. x — X " Eudolium __ Parapholas 0 mm 0 _ _ _ _ Cymatiella [_ u — — — — 3 5 P J _ Crania _ M i Aphera X X _ _ j _____ Lyria —■ OH - _ _ Olive lla — “ ■ Trachycardium ( Ovicardium ) ( Ovicardium ) - x = very warm water o = tropical : J j _

Table I.—Ranges in the New Zealand Tertiary of temperature-index molluscan genera (now living only in warmer seas).

" -^^STAGE GENUS, SPECIES ' ' -- Upper Pliocene Lower Pleistocene Howero Series Recent Wwp Ww Wh Wn Wok Wc Miltha, Polinices, Olivella, Maoricardium, Trachycardium * , • • • Patro (Prismatro) Xenophalium (Xenogalea) ... Calliostoma spectabile group Stiracolpus symmetricus Chlamys delicatula • • Eucominia otakauica • • Ellatrivia Leucotina ambigua Pterynotus angasi powelli V Pterynotus angasi eos Acrilloscala n. sp. — Pecten s. s. Cabestana debilior Cabestana waterhousei segregata Cabestana spengleri Anadara trapezia Capulus Eunaticina Nassarius aoteanus Charonia capax Monoplex austrainsiae A . • - Tonna Heliacus Agnewia

Table ll.—Temperature-index molluscs in the New Zealand Pleistocene.