378 NEW YORK STATE MUSEUM 



had the full benefit of the other's observations. The wonderful homo- 

 geneity in the development of the fauna in these two restricted regions, 

 separated by 129 degrees of longitude, 1 is manifested not alone in the com- 

 position of generic and specific characters of the organisms, but equally in 

 the nature of the sediments. The latter are largely black shales with inter- 

 calated limestone banks. Of the nature of these sediments Holzapfel says : 



The name Domanik is applied to a dark, mostly brown, somewhat cal- 

 careous and strongly bituminous shale with numerous calc concretions, 

 which are arranged in successive layers. These concretions are the situs of 

 immense numbers of fossils and are often completely filled with them while 

 the shale itself contains but few. Once in a while one finds in the latter a 

 compressed cephalopod, while, on the other hand, the shields described as 

 Spathiocaris are quite abundant. Besides the cephalopods the limestones 

 contain numberless Tentaculites and also Entomis and B u c h i o 1 a retro- 

 striata. Gastropods are rare; species of Cardiola are present, and also 

 a peculiar brachiopod which is related to Camarophoria. 



There is nowhere else so complete a parallel in all the factors involved 

 in the homogenic manifestation of the fauna; and, as with these conditions 

 it attains the fullest development of its peculiarities, we may give brief 

 attention to a comparative analysis of the similarities and divergences in 

 these two manifestations. 



Manticoceras. On inspection of the young stages as well as the adult 

 forms of M. intumescens, it is evident that this shell approaches M. 

 pattersoni most closely without attaining in respect to whorl section 

 the progressed adult condition of the latter. As little does it show in early 

 stages the plump, broad whorls of the delayed M. rhynchostoraa. It is 

 interesting to observe that the Domanik form of M. intumescens retains 

 the peculiarities of whorl section of the type of this species from the lime- 

 stone at Oberscheld. We have shown that M. pattersoni and M. 

 rhynchostoma, in adult and gerontic condition, both pass the stage 

 represented by these broad backed shells, the former however very much 

 earlier than the latter. Without difference in umbilication or other external 



1 The location of southern Timan is approximately 67 n., 51 e. ; of western New York 

 (centrally) 43 n., 78 w. 





