96 Transactions. 



directly succeed the other. It is, however, perfectly clear that there is a 

 far closer relationship between the Waihi and Tawhiti beds than between 

 the Waihi and Castleclifi beds. The change from the Tawhiti to the Waihi 

 beds does not in any way suggest that elements of a new fauna were 

 introduced between these periods. On the other hand, the Tawhiti fauna 

 is as closely related to the fauna of Target Gully as it is to the Waihi fauna. 

 And, again, there is no indication of the introduction of new elements to 

 the marine molluscan fauna during that interval of time. 



The various lists that have now been published of the mollusca of 

 many Tertiary horizons near Oamaru enable us to carry this review a 

 little further. These lists appear to indicate a gradually changing fauna ; 

 nowhere does there seem to be an inrush of additional types. The 

 genera that we have in our marine mollusca now were practically all pre- 

 sent at the time that the Target Gully b^ds were deposited. The fauna 

 of that time was certainly richer than the present one. The change that 

 has taken place since then has been of the nature of reduction rather than 

 of addition. We have, then, been forced to the conclusion that from 

 the time the Wangaloa and Hampden beds were deposited until the 

 present day the marine mollusca of New Zealand has shown a gradual 

 development without any important additions at any time from other 

 fauna regions. This, of course, implies that New Zealand has been com- 

 pletely isolated throughout this long interval of time. 



The genera Murex and Trophon, that Hutton* refers to as having 

 reached New Zealand from the Australian region in Pliocene time, have 

 now been collected from Target Gully. The statement of Hutton that 

 Typhis is of Eocene occurrence in Australia and Miocene in New Zealand 

 needs revision, for the Australian Eocene is now generally classed as 

 Miocene, while Typhis occurs as low as the Wharekuri beds in New Zealand. 

 Further and more careful comparison of Australian and New Zealand speci- 

 mens of Pectunculus laticostatus is necessary before any conclusions can 

 be drawn from the time of appearance of the species in the Tertiary rocks 

 of these countries. Dosinia greyi has been recorded from Wangaloa by 

 Marshall. Tt is thus clear that the palaeontological proofs brought forward 

 by Hutton in 1904 of a Tertiary land connection with Australia fall to the 

 ground in the light of the fuller information that has since been acquired. 



It has been frequently suggested that the resemblance between the 

 Miocene fossils of South America and those of New Zealand is so great 

 that it proves that those lands were either actually connected in the middle 

 Tertiary or were separated by a narrow stretch of water only.f Accurate 

 comparisons have shown that many of these identifications were inaccurate, 

 and the number of species common to the two lands has now been reduced 

 by Suter to six only. It is probable, however, that still further com- 

 parisons are required. It is, at any rate, noticeable that the six species 

 referred to do not occur in the same Tertiary horizon in New Zealand, 

 and that half of them occur in our lowest Tertiaries (Wangaloa and 

 Hampden), which are probably equivalent to the Eocene of Europe. 

 Recent work has shown that it is very noticeable that the Cretaceous 

 fossils of Seymour Island are far more similar to the Cretaceous of New 

 Zealand than the Tertiary fossils of the same locality are to those of this 

 country. The Navidad and South Patagoniun Tertian' fossils also are 

 distinctly different from those of New Zealand. 



* F. W. Hutton, Index Faunae Novae Zealandiae, Introduction, p. 18, 1904. 

 t C. Chilton, Subantarctic Islands of New Zealand, vol. 2, p. 805, Government 

 Printer, Wellington, 1909. 



