44b YORKSHIRE TYPE AMMONITES Nov. 



44. AMMONITES MILES, Simpson 

 (Plate XLIV) 



Original Description 

 " 91. A[mmonites] miles. [M. Simpson, 1855, p. 65.] 



[" I. Without a dorsal keel or furrow." p. 35. 

 " b. Armed with distinct spines or tubercles." p. 58.] 



" Volutions 6, exposed, slender ; radii separated by rather wide 

 spaces, terminate near the back in long, pointed spines ; striae numerous, 

 undulating, annular; aperture roundish; diameter 31 in. 



" This is a smooth and more elegant species than the last [A. armatus. 

 Sow.] ; the spines are more distant, and there cannot be reckoned more 

 than two or three striae on each spine. The sides of the outer whorl are 

 often rather flattened, and the spines being long and slender, are very 

 generally knocked off. 



" Inner volutions striated, but without spines or radii. — L.L., 

 R. H. Bay." 



Additional Details 



Simpson, 1884, 97, 98, adds at end " v " after " L.L." (98). 



Remarks 



Stages, conch, serpenticone ; periphery, i ; ornament, 5*. 



Genus, Deroceras, Hyatt, 1867 ; family, Deroceratidae, Hyatt. The 

 geological position given by Simpson is in the valdani-zone : this seems 

 too high, unless there be derivation. 



Result 

 Deroceras miles, Simpson sp. 1855, Charmouthian [hemera armati ?] 

 Robin Hood's Bay, near Whitby. 



