56b YORKSHIRE TYPE AMMONITES May 



56. AMMONITES LIMATUS, Simpson 

 (Plate LVI) 



Original Description 

 " 77. A[mmonites] limatus. [M. Simpson, 1843, p. 41.] 



[" II. With a keel on the back. 

 " a. Outer whorl broad." p. 31.] 



" This greatly resembles some varieties of the last [A. huntoni], 

 but the foliations of the septa are much more simple." 



Additional Details 



Simpson, 1855, 86. — " 150. A. limatus. Simp. — This greatly resembles 

 the last [A. flavus], but the whorls diminish more in thickness, leaving 

 a larger umbilicus ; there are also a few obsolete radii. It is entirely 

 a cast and of a brown colour. — L.L., R.H. Bay." 



Simpson, 1884, 123, as 1855. 



Remarks 



Stages, conch, oxycone ; periphery, 3 (3c ?) ; ornament, 2 (2c ?). 



There are two specimens sent as types : that with suture Hnes 

 marked (Fig. i) is of the brown colour which Simpson notes, and is, 

 therefore, presumably his holotype ; the other (Fig. 2) is a paratype 

 or metatype. It is more rugose than the first, shows auriculoids, and 

 has a rather larger umbilicus : perhaps it is not the same species. Both 

 are quite immature forms. 



Genus, Oxynoticeras, Hyatt, (Gen. U) ; family, Arietidfc. The 

 geological position is not stated : it is presumably L.L. 13. 



Result 



Oxynoticeras limatum, Simpson sp. 1843, Sinemurian, [oxynotum 

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



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