1918 AMMONITES ROTIFER 113c 



Genus, Perisphinctes, Waagen, family, Perisphinctida?, Hyatt. 



Geological. position : not Calcareous Grit. Matrix bluish-grey, rather 

 hard, somewhat arenaceous, with oolite grains in places. Seems nearest 

 to grey sandstone of athleta zone mentioned O.J.G.S., LIX, 1913. pp, 

 153. 154- 



" Williamson preceded (apt. Brown as Curator of the Manchester 

 Natural History Museum, and in 1837 a collection of Williamson's fossils 

 was bought by the Society. He resigned in 1838 and Brown was 

 appointed in same year " (Mr. J. Wilfrid Jackson, F.G.S., in litt. Aug. 3, 

 1917). Brown thus had Williamson's types in charge. He figured 

 rotifer and gamma, but made no mention' of Williamson. Mr. Jackson 

 drew my attention to Williamson's paper, which was read May 9, 1838. 



Result 



Perisphinctes rotifer, Williamson-Brown sp. 1849, Callovian, 

 [athleta zone ?] Scarborough, Yorkshire. 



Comparable Species 



53 27 40 48 



50, 1 Perisphinctes Recuperoi, Gemmellaro, 1872, 

 55, I v, 9-1 1. 



53 



53 



' I Perisph. Recuperoi; Waagen, 1875, xliii, i. 



72[ 4 8], I Id - XUII > 2 - 



48, — Am. convolutus dilatatus, Quenstedt, 1887, 



lxxxi, 1. 

 48, — Id., lxxxi, 4. 



50, — Id., lxxxi, 22. 



Perisph. Recuperoi ; Siemiradzki, 1899, P- 295. 



Dr. Siemiradzki writes " Ouand a P. rotijer, dont vous avez eu 

 l'aimabilite de me communiquer la photographic, il me parait etre identique 

 a P. Recuperoi, Gemm. — ses lobes et la sculpture sont identiques, tout 

 au plus s'il y a une petite difference dans les dimensions — qui d'ailleurs 

 sont assez variables chez P. Recuperoi." — In litt. Mar. 12, 1912. 



The list of Comparable Species is given in accordance with this kind 

 information ; but it may be remarked that Gemmellaro 's figures show a 

 larger specimen with secondary ribs much coarser and fewer, and a 

 reduction in whorl thickness greater than Brown's species might be 

 expected to develop. The horizon of the Sicilian species is Macrocephalus 

 zone. 



