Marshall and Murdoch. — Tertiary Socks near Wanganui. 115 



Art. XX. — The Tertiary Rocks near Wanganui. 



By P. Marshall, M.A., D.Sc, F.G.S., F.N.Z.Inst., Hector and Hutton 



Medallist, and R. Murdoch. 



[Read before the Wanganui Philosojjhical Society, 3rd December, 1919 ; received by 

 Editor, 31st December, 1919 ; issued separately, 10th June, 1920.] 



The marine strata that occur in the neighbourhood of Wanganui have 

 long been the subject of geological inquiry and research. As developed 

 along the coast-line they are richly fossiliferous almost throughout their 

 extent, and the fossils that they contain are so closely related 'to the Recent 

 molluscan fauna that the rocks have always been referred to the higher 

 divisions of the Tertiary era. A resume of the earlier work that had been 

 published on these sediments was given by Hutton (1886, p. 338), and it 

 is in general unnecessary to refer to it here. In that paper also Hutton 

 gave for the first time a fairly complete list of the mollusca that had been 

 collected from the Wanganui system up to that date. The list, however, 

 contains also a number of species that had been found in the strata at 

 Matapiro and Petane, in Hawke's Bay, which were considered by Hutton 

 to be of equivalent geological age. 



In his Wanganui system Hutton included the blue clays at Castleclif? 

 and the blue clays at Patea, but he makes no reference to the rocks that 

 outcrop on the coast between those places — the mouth of the Wanganui 

 River and that of the Patea River. 



A fuller" list, but based upon the same principles and containing 

 descriptions of a number of additional species, was published by Hutton 

 subsequently (1893, }}. 35 et seq.). 



In these papers Hutton rarely makes any statement as to the actual 

 Wanganui locality at which the various species were found. For that 

 reason none of his lists can be utilized in any statement of the species that 

 occur in the beds at Castlecliff and elsewhere along the coast. This is the 

 more regrettable because many of the new species that were described in 

 the Madeaif Memorial Volume were found by Drew in the marine cliffs 

 somewhere to the north of Castlecliff. 



Hutton (1886, p. 337) took this course deliberately, for he says, " In 

 * order to save space I have not thought it necessary to give separate lists 

 of the fossils from each locality, but have contented myself with one list of 

 all the species that have been found in the Wanganui system," but the 

 work that has been done " will enable local geologists to fill in the details." 

 This additional work has hot been done up to the present time, and the 

 details that have to be filled in are so numerous that much time must 

 elapse before anything approaching a complete result is achieved. 



Park (1887) examined all the Wanganui and west-coast district for 

 the Geological Survey, and in his report there are lists of fossils that he 

 collected from the various strata that crop out on the coast-line and on 

 the banks of the Wanganui River, as well as a number of other adjacent 

 localities. The lists that he gives are, however, far from complete, 

 though they reveal the occurrence of a large number of extinct species, 

 such as Pecten triphooki, Pecten semiplicatus, Ostrea ingens, Cardimn 

 spatiosum, and Perna sp., several of which were regarded by Hutton as 

 characteristic of his Pareora system, of Upper Miocene age. 



