Trof. Nichohon — On JEndoeertis in Britain. 



103 



has ever been noted as occurring in Britain ; and my object in the 

 present communication is to describe a British specimen of Endoceras 

 proteiforme, Hall, of which an accurate drawing is given below, to- 

 gether with a magnified portion of the surface. 



The specimen in question was discovered by me in the Graptolitic 

 Mudstones of the Coniston Series of the North of England, and it is 

 one of the few fossils, beyond Graptolites, which have hitherto been 

 detected in this formation. It consists of a much compressed and 

 flattened tube, about two inches and a half in length, and seven- 

 tenths of an inch in breadth. That the walls of this tube were 



Fig. la. Endoceras proteiforme, Hall. Coniston Series. — Skelgill Beck, near Ambleside. 

 16. A small part magnified. 



extremely thin is shown by the fact that the surface of the fossil is 

 thrown into longitudinal folds or corrugations, which are obviously 

 due to compression. No traces of a siphuncle or of septa can be 

 made out. The entire surface of the shell, however, is covered by a 

 cancellated network of very delicate transverse and longitudinal 

 striae, giving it an exceedingly well-marked appearance, and arranged 

 in a very characteristic manner. The transverse stride are about one 

 hundred and twenty-five to one hundred and fifty in the space of an 

 inch, and are decidedly more conspicuous than the longitudinal stri^. 

 Not only is this the case, but they are arranged in fascia, or bands, 

 of three or four approximated striae, separated by somewhat wider 

 interspaces. Where the substance of the shell is preserved, the 

 transverse striae, as above said, are much better marked than the 

 longitudinal strise, and the latter can only be detected by the use of 

 a lens. In places, however, where the fossil has been decorticated, 



