268 Transactions. — Geology. 



Pleurotomaria tertiaria, M'Coy. 



Gryphcea tarda, Hutton (?). 



Terebratella suessi, Hutton. 



Terebratella gaulteri, Morris. 



Terebratella aldinga, Tate. 



Holaster spatangiformis, Hutton. 



Holaster cordatus, Hutton. 



Pericosmus tuberculatum, Hutton. 



Schizaster lyoni, Hutton. 



Flabellum circular e, Tenison- Woods. 

 These are amply sufficient to show that the Cobden lime- 

 stone is the equivalent of the Weka Pass stone, and the Ototara 

 limestone, on the eastern side of the Alps. 



Last March, in blasting the rock, some vertebras and ribs 

 were obtained, and presented to the School of Mines at Grey- 

 mouth. Mr. K. Helms has kindly sent me a drawing of these 

 fossils, upon which I make the following remarks : There are 

 six vertebras, with five ribs on one side and another detached rib 

 lying on the other side ; the vertebras are, I should suppose, the 

 two last dorsal and the first four lumbar. The vertebrae are 

 said to be divided longitudinally down the middle, and they 

 show centra which are cylindrical, considerably longer than 

 broad, and with flat ends. There is no constriction in the 

 middle. The length of the centra increases backwards, so tbat 

 the two posterior are about 4f inches in length by 8£ inches in 

 breadth, and the two anterior vertebrae are about ?>\ inches in 

 length by 2| inches in breadth. These dimensions are not to be 

 considered as accurate, and are only intended to give some idea 

 of the size and proportions of the centra. The neural arches are 

 not seen, owing to the obliqueness of the section ; but what I 

 take to be the transverse processes of one side are exposed. 

 These are nearly as broad as the length of the centra, and with 

 a visible length of nearly twice the diameter of the centra ; they 

 must therefore be longer than this. They are set nearly at right 

 angles to the centra, and have straight, parallel sides. The ribs 

 are very robust, being more than an inch in thickness. 



The centra of these vertebrae show that they are mammalian, 

 and the large size of the transverse processes are either cetacean 

 or sirenian in character. The proportion of length to breadth 

 of the centra is greater than usual, but agrees well with 

 some of the Ziphioid Whales, to which family 1 therefore refer 

 them. 



The association of a Ziphioid Whale with Carrharodon angus- 

 tidens, Aturia ziczac, and Pleurotomaria tertiaria indicates an 

 Upper Eocene or Lower Miocene — i.e., an Oligoccne — age for 

 the Cobden limestone. So long ago as 1861 Sir Julius von 

 Haast pointed out that the series of rocks having the Cobden 

 limestone as its upper member rested unconformably on the 



