1898-1902. No. 32.1 FOSSIL FAUNAS FROM S ERIES B. 43 



a few specimen are found to be quite identical in view of the circum- 

 stance that the two regions are situated more than 35 degrees of latitude 

 (or about 2400 miles) apart. 



As to the detailed stratigraphical relation between the beds in the 

 different localities, or even between the lower and upper pait of the 

 series which are distinguished by Schei, I dare not offer any opinion. 

 Of the four species that are in common with the Keyser-fauna of Mary- 

 land, one is restricted to the lower and one to the upper part, whilst 

 the other two are found in both. Of other common species the new Leper- 

 ditia and Stenochisma deckerensis var. ardica also occurs in both 

 divisions, the latter form but in few and small specimens in the lower 

 one. A considerable amount of time must naturally have elapsed between 

 the deposition of the lowest and highest layers of a marine .series, 1000 

 feet thick, and we find also that most of the forms are restricted to one 

 of the divisions, but it is not on the other hand evident from the faunal 

 aspect that the two divisions, geologically speaking, belong to very 

 different times. 



No near relation to European faunas has been found, and apart 

 from the quite cosmopolitan forms, Lejjt. rhomboidalis, Atrypa reticu- 

 laris, Thecia swinderenana and the Favosites forbesi-v ariety the 

 other species differ from European ones. 



This would not be the place to discuss, on the basis of a small 

 fauna like the above, the Silurian or Devonian character of the Keyser 

 fauna. The corresponding zones of New York and New Jersey have 

 been generally regarded as Silurian, in the "Lower Devonian" of Mary- 

 land the Keyser is considered as the basis of the Devonian. The authors 

 of the stratigraphical portion of this very important monograph, Charles 

 ScHUCHERT, C. K. Schwartz, T. Poole Maynard, and R. B. Rowe, 

 strongly emphasize the fact that the fauna of the Keyser, whilst 

 containing a number of species of Helderberg affinities has also a marked 

 Silurian aspect. 



We may quote from the report p. 118: "These Helderberg species ent- 

 ered the Maryland sea in Keyser time, mingling with the Silurian species 

 which continued to consitute the larger part of the faunas. The Keyser 

 limestone is, therefore, clearly transitional between the Silurian and 

 Devonian. Accepting the principle that the age of a formation is that 

 of its youngest fauna, the Keyser is here referred to the Lower De- 

 vonian although the majority of the species in it are distinctly Silurian". 



That the faunas of the Series B of EUesmereland, when seen 

 detachedly, must be regarded as showing in general a Silurian and not 



