Marshall and Murdoch. — Tertiary Socks near W anganui . 127 



forms a connecting-link between- Waipipi and Nukumaru. The la,rge number 

 of species that is found throughout this thick series of strata is in itself 

 sufficient proof that the series is continuous, and it is interesting to find 

 that so many well-known species of Miocene occurrence rise so high into 

 the Wanganui Tertiaries. In this Wanganui area at least it is possible to 

 determine the upper limits of their occurrence. So far as our collections have 

 given us information the following are the levels at which the specified well- 

 known Miocene species finally disappear. At present it is most convenient 

 to define their position as so-many feet below the highest beds at Castleclift". 



Crepidula gregaria, uncommon 



above 1,200 ft. 

 Lutraria solicla, 2,000 ft. 

 Cytherea enysi, 2,100 ft. 

 Melind zelandica, 2,100 ft. 

 Struthiolaria frazeri, 2,100 ft. 

 Ostrea ingens, 2,100 ft. 

 Cardium spatiosum, 2,700 ft. 

 Pecten triphooki, 2,700 it'. 



Pecten semiplicatus, 3,000 ft. 

 Denialium solidum, 3,500 ft. 

 Paphia curta, 3,500 ft. 

 Natica ovata, 3,500 ft. 

 Natica sagena, 3,-500 ft. 

 Crassatellites, 3,500 ft. 

 Struthiolaria canaliculata, 3,500 ft. 

 Olivella neozelardca, 3,500 ft. 

 Dosinia tnagna, 3,800 ft. 



The highest beds at CastleclifE, the horizon to which these occurrences 

 are referred, are covered unconformably by sands and gravels of volcanic 

 material, which usually have a good deal of included timber, and are referred 

 to the Pleistocene. Thomson has lately called this formation generally the 

 Hawera series. 



It is noticeable that many species which have a Recent occurrence and 

 which are common at Castlecliff are quite absent from our collections at 

 Nukumaru and at Waipipi, though from a lithological standpoint there is 

 little change in the rock, and the conditions of deposition seem to have 

 been substantially the same at Waipipi as at Castlecliff . 



Struthiolaria papulosa was last found one mile north of Kai Iwi, about 

 1,200 ft. below the highest beds at Castlecliff. Struthiolaria vermis was 

 last found at Nukamaru, 2,100 ft. down, and it is very scarce there. 



Pecten medius has not been found below 500 ft., though a shell-fragment 

 probably belonging to this species was found at the mouth of the Okchu 

 Stream,"^ 1,700 ft. down. 



Murex zelandicus has not been found at Nukumaru or at Waipipi, though 

 it has frequently been found in rocks of Miocene age in the Oamaru district, 

 and at Pakaurangi Point in the Kaipara Harbour. Murex angasi and Murex 

 octogonus also have not been found north of Kai Iwi, though they too occur 

 in Middle Tertiary rocks in various parts of New Zealand. 



It does not seem to be the case that any 'importance is to be attached 

 to the absence of these species as an indication of climatic changes on 

 the New Zealand coast-line. The absence of species of Murex and of the 

 Recent species of Struthiolaria might at first suggest a colder climate for 

 the Nukumaru and Waipipi beds, but this idea is at once offset by the 

 fact that Pecten medius and Struthiolaria papulosa both occur at the present 

 day in the most southern of New Zealand waters. As more extensive 

 collections are made and additional localities of this district are examined 

 it may well happen that such small peculiarities will be explained. It 

 is also possible that by careful collecting the development of some of the 

 species that have most recently appeared, such as Pecten medius and 

 Struthiolaria papulosa, may be most definitely traced. On the other hand, 

 it may possibly be found that a few of these species reached these shores 

 from other faunal regions. 



