McKay. — On the Age of the Napier Limestone. 369 



During November of the same year, Mr. S. Percy Smith read 

 before the Auckland Institute a paper on the " Geology of the 

 Northern portion of Hawke's Bay," and, like Mr. Cox, describes 

 an upper and a lower limestone, separated by a great thickness 

 of sands, clays, and conglomerates ; all presumably of tertiary 

 date. 



In 1873, Captain Hutton rejected, as not belonging to the 

 Ahuriri formation, the conglomerate sands and clays in the 

 Cape Kidnappers section, which are described by Hochstetter 

 as the base of the Hawke's Bay series, the higher beds appearing 

 at Sciude Island and at Petane. These beds were considered by 

 Dr. Hector, when he examined the district in 1871, as occupying 

 the position assigned them by Hochstetter. Captain Hutton 

 considered them pleistocene, and later I spoke of them as 

 belonging to the Wanganui series. The position of similar 

 rocks, described by Mr. Cox and Mr. Percy Smith as under- 

 lying the limestones of Scinde Island and the coast to the 

 northward, and the reference of these with the overlying shelly 

 limestones, seemed to call for a revision of the Ahuriri series 

 of Hutton. Other causes, however, brought this about at an 

 earlier date than the publication ot Mr. Cox's report, which did 

 not appear till 1877. 



In a paper read before the Otago Institute on the 24th of 

 October, 1876, Captain Hutton discusses the relation between 

 the Pareora and Ahuriri formations ; in which, referring to the 

 classification of the tertiary formations of New Zealand in his 

 " Catalogue of the Tertiary Mollusca and Echinodermata," 

 speaking of the beds separated and grouped under one or other 

 of these formations, he says : " I have been gradually led to 

 doubt the correctness of this division, and to consider it probable 

 that both ought to be regarded as one and the same formation." 

 He now gives the proportion of recent species found in the 

 Ahuriri formation as being 35 per cent., or, with the same 

 number of species, 12 per cent, more than in 1873. 



Early in 1877 I examined the country between Masterton 

 and Napier ; and in reporting on the geology of this district, I 

 divided the tertiary rocks as I had previously done in 1875, 

 referring the beds overlying the Te Aute limestone to the pliocene 

 period, and the limestones W. and N.W. of the Ahuriri Plain, 

 and in Scinde Island, to the upper part of this higher series ; and 

 later, in August, 1878, I pointed out that these were unconform- 

 able to the Te Aute limestones. This had already been indi- 

 cated by Dr. Hector as their probable relation, in his Progress 

 Beport for 1876-77. 



On the 14th of January, 1885, there was read before the Geo- 

 logical Society of London " A Sketch of the Geology of New 

 Zealaud," by Captain Hutton. In this the author states that the 

 grouping of the tertiary rocks is founded on that given in a former 



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