FOSSIL CEPHALOPODS. 315 



roof over the coal is literally crowded with the 

 elegant Ammonites Jason. 



Mr. W. Hudleston, F.R.S., has remarked on the 

 suddenness with which about forty species of Ammo- 

 nites make their appearance in the Kelloways rock 

 of Yorkshire. He thinks it due to a "regular inva- 

 sion." Fossil Nautili are not unfrequent, both in Lias 

 and Oolite ; and some very pretty ones, cut and uncut, 

 are offered for sale at Whitby, Scarborough, Lyme 



Fig. 318. Ammonites Maniellii. 



Regis, Weymouth, and other seaside places .where 

 fossiliferous strata occur, and where people come with 

 a little scientific taste, more leisure, and most money. 

 The group of Ammonites technically known as Ornati 

 occur plentifully near Scarborough. At Cayton Bay, 

 Filey, and Pickering, in Yorkshire, we have well- 

 known localities for very large Ammonites, such as 

 the easily recognized Ammonites excavatus, A. verte- 

 bralis, A. perarmatus, A. plica tilis, etc. 



