LOWER LIAS OF ROBIN HOOD'S BAY 



133 



1973 Xipheroceras planicosta Buckman; Donovan & Forsey: 9, 

 pi. 3, figs 1, 2 (GSM 25033, Obtusum Zone, Dorset). 



Range. Beds 446.4^153.1, Obtusum and Stellare Subzones; 7 

 specimens. 



Remarks. In addition to those listed above, single examples of 

 Xipheroceras sp. indet. occur in beds 446.32, 453.2 and 453.3. 



Genus BIFERICERAS Buckman, 1913 



Bifericeras bifer (Quenstedt, 1845) 



1845 Ammonites bifer Quenstedt: Quenstedt: 83, pi. 4, fig. 14 



(from Wiirttemberg, Germany). 

 ? 1925a Ophidewceras ziphoides Spath: 138^0, figs 1, 2a, 2b 



(from low in the Oxynotum Subzone, Mill Beck Nab, Robin 



Hood's Bay; originally in Hull Museum, but now destroyed; 



see Donovan & Forsey, 1973: 16). 

 1957 Bifericeras bifer (Quenstedt); Soil: 402, pi. 19, figs 1-7 



(from Wiirttemberg, Germany). 

 1976 Bifericeras bifer (Quenstedt); Schlegelmilch: 58, pi. 25, fig. 



3 ('neotype', from Wiirttemberg, Germany). 

 1990 Bifericeras bifer (Quenstedt); Hollingworth et al: 165, pi. 



2, figs 1-12 (BM C.93398-93409, from the Oxynotum 



Subzone, Somerset). 



Range. Bed 483.1, Oxynotum Subzone; 5 specimens. The de- 

 stroyed holotype of Ophidewceras ziphoides Spath might have been 

 a large example of Bifericeras bifer. 



Bifericeras vitreum (Simpson, 1855) 



1855 Ammonites vitreus Simpson: 46. 



1924 Microceras vitreum (Simpson); Buckman: pi. 529 (holotype, 



WM 462, possibly from bed 486.2). 

 1976 Bifericeras vitreum (Simpson); Schlegelmilch: 146, pi. 25, 



fig. 9 (WM 462). 



RANGE. One specimen in bed 486.2, Oxynotum Subzone. 



Bifericeras donovani Dommergues & Meister, 1992 



PL 8, fig. 3 



1992 Bifericeras donovani Dommergues & Meister: 223, figs 

 5(8)-5(10), figs 7(1), 7(2), 7(3) (holotype), 7(4)-7(l 1) (all 

 from nodules in the lower part of bed 501 . 1 at Wine Haven). 



Range. Occurs only in bed 501.1, base of Taylori Subzone; 18 

 specimens. 



Genus CRUCILOBICERAS Buckman, 1920 



Crucilobiceras densinodulum Buckman, 1923 



1876 



PI. 6, fig. 1 



Aegoceras obsoletum (Simpson); Blake: 276, pi. 7, fig. 1 



(BMC. 17939, from bed 486.3). 

 1923 Crucilobiceras densinodulum Buckman: pi. 442 (holotype, 



from Lyme Regis, Dorset). 

 1926/? Crucilobiceras ornatilobatum Spath: 176, pi. 11, fig. 1 



(holotype, from Lyme Regis, Dorset). 



Range. Beds 486.3-488, Densinodulum and Raricostatoides 

 Subzones; 19 specimens. 



Remarks. The well-preserved C. densinodulum in beds 486.3 (PI. 

 6, fig. 1 ) are unituberculate (ie. have ventro-lateral but no prominent 



umbilical-lateral tubercles), are moderately to finely ribbed on the 

 inner whorls, and are characteristically much more compressed than 

 C. densinodum (Oppel). Small specimens or inner whorls of C. 

 densinodulum are very similar to 'Bifericeras (Hemimicroceras)' 

 subplanicosta (Oppel, 1856) and the relationship between the two 

 (eg. a macroconch/microconch pair or size difference only) has yet 

 to be resolved. 



Genus EODEROCERAS Spath, 1925 



Eoderoceras armatum (J. Sowerby, 1815) 



PI. 5, fig. 9; PI. 8, fig. 2 



1815 Ammonites armatus J. Sowerby: 215, pi. 95. 



1843 Ammonites anguiformis Simpson: 17. 



1843 Ammonites owenensis Simpson: 25. 



1855 Ammonites miles Simpson: 65. 



1880/82 Aegoceras armatum (J. Sowerby); Wright: 340 (1882). pi. 

 28 (1880), figs 1, 2 (SM J18222), 3-5 (SM J18223), both 

 from beds 497-99; non pi. 29, =Eoderoceras pugnax (Buck- 

 man, 1914: 103c). 



1911 Deroceras miles (Simpson); Buckman: pi. 44 (holotype, 

 WM 162, from bed 498 or 499). 



1912 Deroceras anguiforme (Simpson); Buckman: pi. 64 

 (holotype, WM 86, from beds 497-99). 



1912 Deroceras owenense (Simpson); Buckman: pi. 65 (holotype, 



WM 476, from beds 497-99). 

 1926£> Deroceras eusculptum Spath: 175, pi. 10, fig. 3 (BM 



C. 26907, from Lyme Regis, Dorset). 

 1992 Eoderoceras gr. miles (Simpson); Dommergues & Meister: 



231, figs 5(5), 5(7) (from bed 497). 

 2000 Eoderoceras armatum (J. Sowerby); Blau et al: 269, figs 4 



( 1-7), 5 ( 1, 3, 5), 6 ( 1), 7, 8 (from NW Germany). 



Range. Beds 494-499, Macdonnelli and Aplanatum Subzones; 

 62 specimens. 



Type specimen. BM C.67323, Sowerby Collection, from Robin 

 Hood's Bay, probably from bed 497, is here designated neotype. 



Measurements (in mm) 





D Wh 



Wb 



U 



BM C.67323 



128.0 32.0(0.25) 



31.5(0.25) 



69.8 (0.54) 



BM C.67323 



102.0 27.4(0.27) 



- 



53.3 (0.52) 



Remarks. Sowerby (1815: 2 15) stated that many examples of his 

 species, including the specimen that he figured, which was collected 

 by Mr. Strangewayes, came from 'the great Alum-clay formation at 

 Whitby' (a stratigraphical term that was used by Sowerby, Young & 

 Bird, Sedgwick and others for beds that included ones as low as the 

 Upper Sinemurian/Lower Pliensbachian clays). Sowerby did not 

 mention any other locality in his original description, so it is not 

 possible to agree with Spam's (1925a: 137, 167) statements that 'the 

 true D. armatum apparently does not occur in Yorkshire', and 

 'Sowerby's type is not preserved in the BM . . . and has always 

 seemed to me to be more like a Charmouth than a Whitby specimen' , 

 nor with Donovan's (1958: 32) opinion that 'Sowerby's type speci- 

 men . . . was almost certainly obtained from the Dorset coast'. It is 

 not permissible to transfer the type locality to Dorset on the opinion 

 that the Yorkshire specimens are morphologically different from 

 those in Dorset, or the belief that the pyritic preservation and 

 frequency of decay perceived from Sowerby's figure are more 

 reminiscent of Dorset examples. The Yorkshire specimens are not 

 morphologically different from those in Dorset (two especially fine 



