124 



M.K. HOWARTH 



1961 



3 (BM C.3124, a large specimen that is very similar to 

 specimens from bed 45 1 ; it is more involute and has higher 

 whorls than sagittahum). 



Asteroceras stellare (J. Sowerby); Dean etal. : pi. 67, fig. 2 

 (lectotype, BM 43969a, from Dorset). 



Range. Beds 447-45 1, Stellare Subzone; 19 specimens. 



Remarks. A. stellare is a large species, and is more involute and 

 has more massive whorls than A. obtusum. 



Asteroceras blakei Spath, 1925 



1925a 



PI. 2, fig. 



Asteroceras blakei Spath: 264, fig. 5 (holotype, BM C. 1999 1 ; 

 from beds 452^155.4, probably 452-53). 

 1925a Asteroceras marstonense Spath: 267, fig. 7 (holotype, BM 

 37948, probably from bed 452 or 453). 



Range. Beds 452-455.4, Stellare and Denotatus Subzones; 29 

 specimens. 



Remarks. A. blakei occurs at a higher stratigraphical level, and is 

 more involute and more compressed than A. obtusum. A. marstonense 

 is a synonym, and its holotype comes from Robin Hood's Bay 

 despite being named after Marston Magna, Somerset. 



Genus AEGASTEROCERAS Spath. 1925 



Aegasteroceras sagittarium (Blake, 1876) 



1876 



PL 1. fie. 7 



Aegoceras sagittarium Blake: 276, pi. 7, figs 2A (lectotype. 



SM J 18230), 2B (paralectotype, BM C. 1 788 1 ). 

 1880/82 Aegoceras acuticostatum Wright: 371 (1882), pi. 35,figs 1- 



3 (1880) (holotype, SM J 18230); objective synonym of 



Aegoceras sagittarium Blake, 1876. 

 1882 Aegoceras sagittarium Blake; Wright: 355, pi. 52, figs 4, 5 



(BM C.1873); pi. 52A, figs 3, 4 (BM C.1873), 5 (BM 



C.1874), 6 (BMC. 1875). 

 1925a Aegasteroceras simile Spath: 265, fig. 6a (holotype, BM 



C.26687). 

 1966 Aega.?ferocera.s , «7M//eSpath;Guerin-Franiatte:310,pl. 189 



(BM C.26687). 

 1966 Aegasteroceras sagittarium (Blake); Guerin-Franiatte: 312, 



pi. 192, fig. 1 (SMJ18230). 



Range. Beds 454. 1-458.1, Stellare and Denotatus Subzones; 123 

 specimens; all the figured ones are from beds 454.2 or 456, probably 

 the latter. 



Aegasteroceras crassum Spath, 1925 



PL 2, fig. 4 



1 882 Aegoceras sagittarium Blake; Wright: 355, pi. 52A, figs 1 , 

 2 (BM C.1922, from bed 458.2 or 458.3, holotype of 

 Aegasteroceras crassum Spath, 1925). 



1925a Aegasteroceras crassum Spath: 266. 



Range. Beds 449^158.3, Stellare and Denotatus Subzones; 9 

 specimens. 



Genus CAENISITES Buckman, 1925 



Caenisites turneri (J. de C. Sowerby, 1824) PL 2, figs 3, 5 



1824 Ammonites turneri J. de C. Sowerby: 75, pi. 452, upper 



figure. 

 1879/81 Arietites turneri (J. de C. Sowerby): Wright: 292 (1881), pi. 



12, fig. 4 ( 1 879) (lectotype, BM 43973a, from Glacial Drift, 



Norfolk). 



1956 



1961 



Euasteroceras turneri (J. de C. Sowerby); Arkell: 760. pi. 

 31, fig. 1 (BM 43973a). 



Caenisites turneri (J. de C. Sowerby); Dean et al.\ pi. 66, 

 fig. 2 (from Bredon Hill. Worcestershire). 



Range. From beds 433.3 and 435, Birchi Subzone: 26 specimens. 



Caenisites brooki (J. Sowerby, 1818) 



1818 Ammonites brooki J. Sowerby: 203. pi. 190. 



1961 Caenisites brooki (J. Sowerby); Dean et al.\ pi. 66, fig. 1 



(BM C.5606, from Charmouth, Dorset). 

 1966 Caenisites brooki (J. Sowerby); Guerin-Franiatte: 325, pi. 



210 (holotype, OUM J. 16020, from Lyme Regis, Dorset). 



Range. From beds 431.2^133.3, Brooki and Birchi Subzones; 1 1 

 specimens. 



Remarks. One of those from bed 431.3 is notable in being 

 extremely large: before removal from the rock, it was measured by 

 Bairstow as 585 mm diameter. The outer part was not recovered, but 

 the portion now preserved in the collection is 445 mm diameter and 

 has a massive, almost smooth outer half whorl with keel and grooves 

 on the venter. The inner whorls are covered in matrix and probably 

 crushed. 



Genus EPARIETITES Spath, 1924 



Eparietites impendens (Young & Bird, 1828) 



PI. 1, fig. 6; PL 4, fig. 1 



1828 Ammonites impendens Young & Bird: 266. 



1855 Ammonites denotatus Simpson: 76. 



1855 Ammonites tenellus Simpson: 97. 



1876 Arietites impendens (Young & Bird); Blake: 290, pi. 6, fig. 



7 (BMC. 17936). 

 1878/81 Arietites collenoti (d'Orbigny); Wright: 304 (1881), pi. 6 



(1878), fig. 1 (BMC. 1881; probably from bed 464.32), pi. 



22B, figs 1-3 (holotype of Ammonites denotatus, SM J3273). 

 1912 Arietites tenellus (Simpson); Buckman: pi. 54 (holotype, 



WM 293, probably from bed 461 or 464.32). 

 1912 Arietites denotatus (Simpson); Buckman: pis 67A, B 



(holotype, SM J3273). 

 1919 Arietites impendens (Young & Bird); Buckman: pi. 120 



(holotype, WM 292, from bed 462 or 464. 1 ). 

 1961 Eparietites denotatus (Simpson); Dean et ah: pi. 66, fig. 4 



(BMC.17936). 



Range. Beds 457-464.32, Denotatus and Simpsoni Subzones; 57 

 specimens; all the figured specimens are from beds 461^64. 



Remarks. Both denotatus and tenellus are synonyms of E. 

 impendens; the best type specimen is the holotype of Simpson's 

 denotatus. but it is clearly the same as the holotype of Young & Bird's 

 impendens. and the holotype of tenellus differs only in having the 

 crushed-flat type of preservation that is common at some horizons. 



Eparietites bairstowi sp. nov. 



PL 2, fig. 8; PL 3 



Holotype. CA 3217, from bed 455.2, lower part of Denotatus 

 Subzone. 



Paratypes. CA 3218 and 3219, from bed 455.5, lower part of 

 Denotatus Subzone. 



DIAGNOSIS. An evolute species of Eparietites in which the umbili- 



