Weller — Kinderhook Faunal Studies. 11 



shell been observed, and yet the fossils are not strictly inter- 

 nal casts for there is no cavity remaining from which the 

 shell itself has been dissolved. Furthermore, many of the 

 specimens preserve the most delicate surface markings. 

 From the nature of the fossils it seems as if the calcareous 

 substance of the shells was removed soon after they were 

 buried, before the sediments were consolidated, and that the 

 cavities thus formed were closed by pressure. In this manner 

 the delicate external markings have in some cases been per- 

 fectly preserved, while in other specimens it is the form of 

 the interior which remains. Now, in the consolidated rock, 

 these planes along which the cavities were closed, split more 

 easily than the rock itself, and consequently we are enabled 

 to secure the form of the fossils. 



The fact that worm burrows seem to penetrate fossil shells 

 in some cases, indicates further that the shells themselves 

 were removed before the sediments were consolidated, when 

 they were still soft enough to allow the worms to burrow 

 through them in all directions. 



This manner of occurrence may account for the apparent 

 general absence of fossils from the formation. They may 

 have been everywhere abundant originally, but with the 

 removal of the shells, and the consolidation of the sediments, 

 all traces of them may have been usually destroyed. In only 

 some favored localities, such as Northview, were there present 

 some conditions not fully known to us, which prevented the 

 sides of the cavities left by the removal of the shells, from 

 adhering as closely as the other portions of the matrix. 



Descriptions of Species.* 



COELENTERATA. 



Zaphrentis sp. 



Among the Northview fossils two small specimens of corals 

 have been observed which apparently belong to this genus, 



* From these descriptions tlie bibliographic references have been omitted. 

 For these the reader is referred to Bulletin 153, U. S. Geological Survey, 

 "A Bibliographic Index of North American Carboniferous Invertebrates", 

 by Stuart Weller. Washington. 1898. 



