86 Transactions. 



There are only thirty-four species in this list, and many of them are 

 represented by fragmentary material only, or they are filled with a hard 

 and tough matrix. The hinge-teeth and apertures of many of the species 

 are obscured, and this makes the identification a little uncertain. Only 

 seven of the species are certainly Recent, and the percentage of Recent 

 species therefore falls as low as 21. The small size of the collection, the 

 fact that large species only were in a condition to be collected, and the 

 uncertainty of identification in some cases make it unsafe to rely too closely 

 on this percentage in correlating the strata with those of other localities 

 in New Zealand. 



The nature of the mollusca points rather to the Target Gully horizon, 

 for there are only six species that do not occur there, and these species 

 are found in horizons of much the same position near Oamaru or in the 

 Trelissick Basin. On the other hand, the fauna of this stratum is of a 

 distinctly older type than that of any of the coastal localities of the 

 district in which we have collected fossils up to the present time. 



Art. XII. — Tertiary Rocks near Hawera. 



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



and R. Murdoch. 



[Read before the Wanganui Philosophical Society, 25th October, 1920 ; received by Editor, 

 31st December, 1920 ; issued separately, 27th June, 1921.] 



In the last volume of the Transactions of the New Zealand Institute we 

 published lists of fossils from various localities on the coast-line to the 

 north-west of Wanganui. During the past year we have been able to 

 make collections on the beach at Hawera, some twenty miles farther along 

 the coast in the north-west direction. Throughout this distance the rocks 

 are of the same general nature as they are near Wanganui — in other words, 

 micaceous sands and clays (the papa rock). If anything, the material is 

 rather more sandy on the average than it is farther south. There is 

 perhaps rather less mica, and black grains are rather more numerous among 

 the quartz-grains. The strike of the strata changes a good deal. As 

 stated in our former paper, the strike between Castlecliff and Nukumaru is, 

 on the average, 70°. By the time Patea is reached it is as much as 100°, 

 and still farther north, at the mouth of the Tangahoe Stream, on the coast 

 opposite Mokoia, it is 145°. This shows clearly that there is a gradual 

 swing in the strike as one proceeds to the north-west. The dip is always 

 to the south-west and is always slight, and has an average of about 4°. 



The direction of the strike and dip as related to that of the coast is 

 such that older and older beds are exposed as one journeys north until the 

 mouth of the Tangahoe is reached. At this point the trend of the coast 

 is parallel to the strike of the strata, and as one goes still farther north 

 younger and younger strata again begin to make their appearance. About 

 500 ft. of strata separate the lowest horizon three miles north of Waipipi 

 from the horizon at the mouth of the Tangahoe Stream. The Waihi beach 



