596 LIASSIC DENTALIID^. [NOV. I906, 



are confined within a few feet vertical, but extend from Huntcliff 

 to Eobin Hood's Bay, some 25 miles, wherever there is an exposure. 

 The form then disappears as suddenly as it came into existence. 



Mr. E. T. Newton remarked on the difficulty of discussing a 

 paper of this character, and enquired to what extent the Author 

 had referred the Dentaliidse to particular zones. 



Prof. Watts, in reply, read a portion of the paper including a 

 description of one of the new species of Dentalium. 





