132 STUART WELLER 



and is probabl)^ identical with one of the common Chouteau 

 species of the genus. Ambocoelia parva was first described from 

 the Northview sandstone, and the specimens from the shale 

 seem to be indistinguishable from the types of the species 

 except that they are more or less crushed. No crustaceans are 

 recorded by Williams, but Phyllocarid crustaceans similar to 

 those noticed in the fauna are not of uncommon occurrence in 

 similar shale formations. Fish remains were detected by Wil- 

 liams in the Arkansas beds. No specimens of the Leiorhynchns 

 subspahda noticed by Shepard 1 from this locality were detected 

 by the writer. 



Notwithstanding the presence of some forms in this fauna at 

 Frazer's which have not yet been recognized in the Eureka 

 shale of Arkansas, and the absence of others which are known 

 to occur there, when we consider the poorly preserved nature of 

 the fossils in all the localities and the stratigraphic relations of 

 the beds containing them, the similarity between the faunas of 

 the two regions is sufficient to establish the correlation, in a 

 general way, of the beds containing them. 



In regard to the age of the Eureka shale fauna in Arkansas 

 Williams 2 says : 



The fauna of these fine shales in Arkansas, terminating and following 

 the black shales, is unmistakably much higher than the Genesee black shale 

 of New York. Faunally it is the correlative of the Louisiana or lithographic 

 limestone, and is thus as late as the Kinderhook stage of the Eocarbon- 

 iferous. 



The beds indicated in the quotation are the fine green shales 

 which always follow without any break in the sedimentation, the 

 typical black Eureka shale when the two members are both 

 present. Usually the black shales, in Arkansas, contain almost 

 no fossils save Linguhis, but at one locality on War Eagle Creek 

 a fauna from the black shales is noted which does not differ 

 essentially from that in the greener beds. 



Recent careful studies among the Kinderhook faunas of 

 the Mississippi valley have given a basis for a more definite 



1 Loc. cit., p. 67. 2 I.oc. cit., p. 149. 



