306 Dr. l. f. spath on [vol. lxxix, 



merely the indifferent ammonite genera Phylloceras, Lytoceras, 

 and Haploceras. At any rate, the zone of Oppelia lithographica, 

 Haug's lowest zone of the Tithonian, contains Waagenia hybonota 

 of the steraspis zone, and is thus of Middle Kimmeridgian age. 



The Upper Kimmeridgian genus Pseudovirgatites has prohahly 

 often been confused with the much later Virgatospliinctes. The 

 other Virgatitid genera are usually believed to be confined to the 

 'boreal' province, and the term A r olgian has been introduced for 

 these Upper Kimmeridgian Beds. But the difficulty now arises of 

 placing the Aquilonian, or the Russian Graspedites zones which 

 are put by recent writers like Salfeld as equivalents of the 

 Purbeckian, whereas Abel, 1 in 1897, had correlated the Upper and 

 Lower Volgian, including the ' Riasan horizon,' with the Upper 

 Tithonian. 



The Graspedites zones follow on beds that have been considered 

 to be Portlandian, though probably wrongly, as stated above. They 

 are overlain unconf ormably by the Riasan Beds with a characteristic 

 new genus of Berriasellidae, namely Kiasanites. gen. nov. (group 

 of Hoplites rjasanensis (Lahusen) 2 ), and, according to Kilian, 3 

 P. rjasanensis has been rediscovered in the Upper Tithonian of 

 the Rhone Basin. 



These Graspedites beds are thus well down in the Jurassic, and 

 their ammonite fauna consists of the genera Graspedites, Kach- 

 purites, and Gamier iceras. In the Knoxville Beds, the genera 

 Durangites, Kossmatia, and Stenoceras are associated with a 

 ''Graspedites'' (' Olcosteplianus'' mutabilis Stanton 4 ); but there is 

 a contemporary of Kossmatia: namely, Gray iceras (group of Sim- 

 birskites nepalensis Gray sp., and S. mexicanns Burckhardt), 

 which also resembles these Craspeditids. On the other hand, the 

 Graspedites of the Upper Volgian are supposed to be close to 

 those of the Riasan Beds, and Pavlow 5 recognized six species of 

 the latter as being found also in the beds with ' Oxynoticeras ' and 

 ' Graspedites ' stenomphalus of the district of Alatyr (Russia). 

 Bogoslowski 6 thought the latter even younger, which would make 

 them undoubtedly Cretaceous ; but it may be recalled that the 

 'Oxynoticeras'' described by Stchirowski have also been identified 

 with the Garniericeras of the Upper Volgian. In reality, there 



1 ' Die Tithonschichten von Niederfellabrunn, &c.' Verhandl. K.K. Geol. 

 Reichsanst. Nos. 17-18 (1897) p. 360. 



2 In Bogoslowsky, ' Der Rjasan-Horizont, &c.' Mater. Geol. Russl. vol. xviii 

 (1897) p. 142 & pi. t, figs. 3-4. 



:i ' Notice Stratigraphique sur les Environs de Sisteron, &c.' Bull. Soc. 

 Geol. Prance, ser. 3, vol. xxiii (1895) p. 684. 



4 ' The Fauna of the Knoxville Beds ' Contrib. Cret. Pal. Pacif. Coast, 

 Bull. U.S. Geol. Surv.No. 133 (1895) p. 77 & pi. xv, figs. 1-5 : probably three 

 species of Subcraspeclites (referred to Simbirskites by Uhlig, op. cit. 1911, 

 p. 354). 



5 ' Le Cretace Inferieur de la Russie & sa Faune ' Nouv. Mem. Soc. Imper. 

 Natural. Moscou, vol. xxi, livr. 3 (1901) p. 39. 



fi ' Materialien zur Kenntnis der Untercretacischen Ammonitenfauna von 

 Central- & Nord-Russland ' Mem. Com. Geol. St. Petersb. n. s. vol. liv, livr. 2 

 (1902) table on p. 160. 



