LOWER LIAS OF ROBIN HOOD'S BAY 



ICoroniceras (Arietites) radiatus (Simpson, 1843) 



1 843 Ammonites radiatus Simpson: 47 (non Ammonites radiatus 



Bruguiere, 1789). 

 1911 Arietites radiatus (Simpson); Buckman: pi. 35 (holotype, 



WM 304, possibly from beds 426^129, but it is only 1 2 mm 



diameter and is not identifiable). 



Coroniceras (Arietites) cf. planaries (Reynes. 1879) 



1878/81 Arietites nodulosus (Young & Bird); Wright: 288 (1881), 

 pi. 6, figs 2, 3 (1878) (C.1880, possibly from beds 426- 

 429). 



Genus ARNIOCERAS Hyatt, 1867 



Arnioceras semicostatum (Young & Bird, 1828) 



PI. 1, fig. 2 



1828 Ammonites semicostatus Young & Bird: 257, pi. 12, fig. 10. 



1855 Ammonites vetustus Simpson: 88. 



1876 Arietites semicostatus (Young & Bird); Blake: 288, pi. 5. 



fig. 4a (upper figure, BM C. 17935; lower figure, BM 



C. 17934 (?malformation); both from Redcar). 

 1876 Arietites difformis (Emmrich); Blake: 289, pi. 6, fig. 3 



(C. 17933, possibly from Redcar). 

 1889 Arnioceras semicostatum (Young & Bird); Hyatt: 165, pi. 2, 



figs 12, 13 (from 'Whitby', presumably from Robin Hood's 



Bay). 

 1918 Arnioceras semicostatum Buckman: pi. 1 12 (holotype, WM 



924). 

 1925a Arnioceras semicostatum (Young & Bird); Spath: 329, fig. 



10a(BMC.86a). 

 1931 Arnioceras semicostatum (Young & Bird); Jaworski: 1 1 1, 



pi. 5, fig. 1 (WM 924). 

 1956 Arnioceras semicostatum (Young & Bird); Spath: 153, pi. 



10, figs 6 (BM C.25651), 7 (BM C.17933). 



1961 Arnioceras semicostatum (Young & Bird); Dean et al.\ pi. 

 65, fig. 4 (BM C.25651). 



1962 Arnioceras vetustum (Simpson); Howarth: 103, pi. 15, fig. 

 2 (holotype, GSM 26404, ?from bed 421 or 424). 



1976 Arnioceras semicostatum (Young & Bird); Schlegelmilch: 

 138, pi. 21, fig. 4 (WM 924). 



RANGE. Beds 42 1 .4-^129.64, Sauzeanum Subzone; 1 1 8 specimens. 



Remarks. Jaworski's (1931: pi. 5, fig. 1) enlarged figure of the 

 holotype is much better than Buckman's (1918) figure. Older collec- 

 tions contain many well-preserved Arnioceras semicostatum from 

 limestone nodules. Such good specimens were not found by Bairstow 

 and they have sometimes been considered to come from Glacial 



121 



Drift, but judging from the preservation it is possible that they came 

 from nodules near the top of bed 42 1 .4 or from beds 424.2 or 424.3. 

 Although Arnioceras persists elsewhere into the overlying Brooki 

 and Birchi Subzones, all the well-preserved Robin Hood's Bay 

 specimens appear to have come from these limestone nodules of the 

 Sauzeanum Subzone. One of the better examples in Bairstow's 

 collection is figured in PI. 1, fig. 2. 



The range of Arnioceras is extended down to bed 42 1 . 1 and up to 

 beds 430-436 by six specimens of indeterminate species found by 

 Bairstow. 



Arnioceras acuticarinatum (Simpson, 1855) 



1855 Ammonites acuticarinatum (Simpson): 94) 



1911 Arnioceras acuticarinatum (Simpson); Buckman: pi. 40 



(holotype, WM 295; ?from beds 421^24). 

 1 93 1 Arnioceras acuticarinatum (Simpson): Jaworski: 1 26, pi. 5, 



fig. 2 (WM 295). 

 1976 Arnioceras acuticarinatum (Simpson); Schlegelmilch, 



1976: 138, pi. 21, fig. 3 (WM 295). 



REMARKS. The best figure of the holotype is that of Jaworski, and 

 such a well-preserved specimen might have come from beds 421 — 

 424. Its more finely ribbed inner whorls possibly separate it from A. 

 semicostatum. 



Arnioceras miserabile (Quenstedt, 1856) 



1856 

 1876 



1884 



1925« 



1976 



Ammonites miserabilis Quenstedt: 71, pi. 8, fig. 7. 

 Aegoceras nigrum Blake: 274, pi. 6, fig. 6 (lectotype, BM 

 C. 17889, possibly from bed 424.2 or 424.3). 

 Ammonites miserabilis Quenstedt; Quenstedt: 106, pi. 13, 

 figs 27-30. 



Arnioceras nigrum (blake); Spath: 329, fig. 10b (BM 50150c, 

 possibly from bed 424.2 or 424.3). 



Arnioceras miserabile (Quenstedt); Guerin-Franiatte: 254, 

 pi. 136, figs 1 (neotype, from Germany, original of Quen- 

 stedt, 1 884: pi. 21 , fig. 27), 2-4 (from Germany and France). 

 Arnioceras miserabile (Quenstedt); Schlegelmilch: 49, pi. 

 21, fig. 5 (neotype). 



RANGE. Beds 424.2^425.5, Sauzeanum Subzone; 7 specimens. 

 Genus VERMICERAS Hyatt, 1889 



Vermiceras multanfractum (Simpson, 1855) 



1855 Ammonites multanfractus Simpson: 95. 



1962 Vermiceras multanfractum (Simpson); Howarth: 101, pi. 

 14, fig. 6 (neotype, WM 281); not found by Bairstow, possibly 

 derived from Glacial Drift in Robin Hood's Bay. 



PLATE 1 



Fig. 1 Tragophylloceras numismale (Quenstedt). Bed 505.2, CA 2744. 



Arnioceras semicostatum (Young & Bird). Bed 424.2, CA 2830. 



Lytoceras fimbriatum (J. Sowerby). Bed 576.4, CA 2778, x 0.6; the large outer whori is part of the body chamber. 



Asteroceras confasum Spath. Bed 446.32, CA 3010. 



Euagassiceras resupinatum (Simpson). Bed 422.2, CA 2948. 



Eparietites impendens (Young & Bird). Bed 461, CA 3228. 



Aegasteroceras sagittarium (Blake). Bed 456, CA 3124. 



Coroniceras (Arietites) alcinoe (Reynes). Bed 429.64, CA 2803, x 0.6; the asterisk marks the probable end of the phragmocone. 

 All figures natural size, except Figs 3 and 8. 

 Where determinable the position of the end of the phragmocone is marked with an asterisk (*) on all specimens figured in the plates. 



Fig. 2 

 Fig. 3 

 Fig. 4 

 Fig. 5 

 Fig. 6 

 Fig. 7 

 Fig. 8 



