lyb YORKSHIRE TYPE AMMONITES Mar. 



17. AMMONITES BELCHERI, Simpson 

 (Plate XVII) 



Original Description 

 " 13. A[mmomtes] Belcheri. [M. Simpson, 1843, p. 12.] 



[" I. Without a dorsal keel or furrow. 

 " a. No spines." p. 7.] 



" Depressed ; volutions 6 or 7, exposed, rather flat on the sides, 

 back rounded ; radii straight, prominent, obsolete on the back, separated 

 by concave spaces ; aperture squarish ; diameter, i^ inch. 



" The smoothness and elegance of this beautiful shell reminds me 

 of the politeness and urbanity of H. Belcher, Esq., President of the 

 Whitby Philosophical Society, whose love for natural science, also, 

 entitles him to a grateful remembrance. It is from the lower Lias, 

 and may be readily distinguished from A. gagateus and others by the 

 smooth back." 



Additional Details 



Simpson, 1855, p. 43, omits " depressed," adds, after " prominent," 

 " obtuse," has, instead of second par., " A cast, L. L. ; R. H. Bay [Lower 

 Lias, Robin Hood's Bay]" ; 1884, p. 72, adds after name, " Pal., pi. xv., 

 f. 7 " [Wright's, Mon. Lias Amm.]. 



Remarks 



Stages, conch, serpenticone ; periphery, i ; ornament, 4. 



The inner whorls up to about 5 mm. diameter are smooth ; there is 

 just the slightest sign of angulation of the periphery, and across it, in a 

 strong light, can be seen very small ribs and intermediate striae, with 

 forward bends. The body chamber is half of the last whorl. Though 

 Simpson says the specimen is a cast, yet there is a thin film of test on 

 the air-chambers, obscuring the suture-Hnes. The pattern can only be 

 followed approximately. It is simple, like that given by d'Orbigny 

 for A. torus, with oblique L'-, L' : the EL is slightly displaced. 



Genus, Caloceras, Hyatt, 1870, 29, — family Caloceratidas, S. Buckman, 

 1906, 233. The geological position would be just above the planorbis-zone. 



Result 



Caloceras belcheri, Simpson sp., 1843, Hettangian [megastoma- 

 zone], Robin Hood's Bay, near Whitby. 



