366 NEW YORK STATE MUSEUM 



the G. cf. d o m an i cense Holz., but in the Genundewa limestone of the . 

 east and in the Cashaqua shales of both east and west there are species of 

 this genus. The specially interesting Probeloceras lutheri, Belo- 

 ceras iynx and Sandbergeroceras syngonum are not known 

 nor are the genera recognized in the Chautauqua subprovince. Bactrites is 

 common to both faunas but not in species. We recognize in the west, in 

 accordance with the many other European affiliations of that fauna, B. cf. 

 subflexuosus, in the east B. aciculum and B. g r a c i 1 i o r. 



The mode of occurrence of Clymenia is noteworthy. It is known in 

 the Naples subprovince only, and, though it occurs as far west as Java, it 

 does not pertain to the Chautauqua fauna. Nor does it occur at a specific 

 or high horizon in the rocks, but, on the contrary, the fauna is long con- 

 tinued in typical expression after its disappearance. Herein is a noteworthy 

 convergence from the differentiation of facies exhibited by the European 

 sections. Most marked among the faunal differences are the presence and 

 often profusion of Euthydesma, Kochia, Loxopteria in several species, 

 Praecardium and Elasmatium in the Chautauqua subprovince and their 

 exclusion from more eastern sections, and by contrast the abundance of the 

 coarsely plicated forms of Lunulicardium (Pinnopsis) in the east and their 

 absence in the west. Throughout the lamellibranchs it is noticeable that 

 species common to both subprovinces if abounding in one are unusual in the 

 other. It will be observed that, so far as we understand the succession of 

 fossils in the Chautauqua region, there is no sequential appearance of the 

 leading fossils such as M antic, rhynchostom a, Euthydesma, Kochia, 

 Loxopteria and Praecardium, on the contrary they appear now to be pretty 

 uniformly distributed through the Silver Creek, Angola and Portland gray 

 soft shales and, with the other members of the assemblage, to correspond to 

 the sedimentation. This uniformity of distribution is equally manifested in 

 the leading species of the Naples subprovince. Minuter assemblages recur- 

 ring at brief intervals through the strata of course vary somewhat in their 

 combination, but the significance of such variations is here as in other cases 

 in the sequence of faunas, of very minor importance save as they may serve 



