92 Transactions. 



to say that a comparison of the mollusca of the Castlecliff beds with the 

 .Recent mollusca shows definitely that New Zealand did not at that time 

 receive additions of any importance whatever to its marine molluscan 

 fauna, and therefore that any extension of the area of New Zealand at 

 that time did not in any way impair its isolation. 



Park* has stated that during the Pleistocene the area of New Zealand 

 was many times greater than now, that the whole of the South Island and 

 most of the North Island was glaciated, and in a map he shows the land 

 extending to New Caledonia The general similarity between the fauna 

 of the Castlecliff beds and the Recent fauna goes far to disprove the idea 

 of glaciation of this district, while there is no evidence known to us, so far 

 as the mollusca are concerned, that would show a Pleistocene extension 

 of New Zealand to New Caledonia. Hutton in various other publications 

 urged not only that New Zealand was greatly extended during the early 

 Pliocene, but also that it was heavily glaciated at that time. It is probable 

 that in the rock-series that we have described the Nukumaru series is about 

 the age of the early Pliocene. In these beds we have at once a proof that 

 this part of New Zealand was not elevated at that time, and we also have 

 distinct proof that the climate was no colder, but was probably a good 

 deal warmer than at the present day. 



There are, however, clear proofs that New Zealand, or at least this part 

 of the country, was considerably elevated at the close of the time of deposi- 

 tion of the Castlecliff beds. Two of these may be quoted. Artesian wells 

 in the lower valley of the Wanganui River bed have reached a depth of 

 400 ft. without passing through the alluvia] matter that the river has 

 deposited. The valley of the Waingongoro Piver had a bed that extended 

 to an unknown depth below the present sea-level, and had a width of about 

 half a mile at the present beach-level. In addition to these facts, the 

 strata of the series of rocks, that has been described have all been elevated 

 and eroded off to a uniform level before the next series of rocks was 

 deposited. This upper rock-series rests in all cases unconformably on those 

 that we have described, lying directly on the Whakino-Waihi beds in the 

 extreme north of the district at which we have worked. The general occur- 

 rence of the sediments suggests that all the overlying beds were removed by 

 erosion before these Pleistocene sediments were deposited. As to the precise 

 age of this upper series of rocks we have at present no exact information. 

 They frequently contain a large number of molluscan fossils at the base, 

 but we have seen no extinct species of mollusca among them, and it is 

 probable that they are approximately equivalent to the Pleistocene of 

 Europe. Thomson has lately proposed to apply the name " Hawera 

 series " to them. There is no particular objection to this, though the term 

 " Pleistocene " has long been used in New Zealand, and it has not yet 

 been shown that they are not a reasonable equivalent of the European 

 Pleistocene. 



It is perhaps advisable to recapitulate that after the Castlecliff series 

 had been deposited there was a prolonged period of moderate elevation 

 during which a great deal of erosion took place. Though this elevation 

 was considerable, it was not great enough to bring the New Zealand area 

 sufficiently close to any other country to allow of the introduction of any 

 new features into the marine molluscan fauna of New Zealand. 



The work that has been done in recent years on the fossil and Recent 

 mollusca of New Zealand is now of sufficient amount and importance 



* J, Park, Geology of New Zealand, p. 14, 1910 



