CHAPTER III. 



STRATIGRAPHIC AND GEOGRAPHIC DISTRIBUTION OF AMPHIBIA IN THE COAL 



MEASURES OF NORTH AMERICA. 



There are but four localities in North America which have furnished any notable 

 remains of Amphibia in the Coal Measures. These are, in the order of their dis- 

 covery, the deposits at the South Joggins, Nova Scotia; the Linton, Ohio, Coal Meas- 

 vires; the Mazon Creek, Illinois, shales; and the Cannelton slates near Cannelton, 

 Pennsylvania. There are, however, several other localities on the continent which 

 have furnished evidences of Amphibia in the Coal Measures. The principal one of 

 the latter localities is doubtfully of Coal Measures age, although recent discoveries 

 would tend to show it is such. The deposits in question, those of the Clepsydrops 

 shales of Vermilion County, Illinois, have, heretofore, been regarded as Permian, 

 but the discovery of similar remains in 

 rocks of undoubted Pennsylvanian age in 

 Pennsylvania would seem to indicate that 

 the Illinois deposits were contemporaneous 

 with them. 



(a) The deposits in Vermilion County, 

 Illinois, lie along the north bank of Salt 

 Fork Creek, at the tip of the "Horseshoe 

 Bend," about 2 miles south of Oakwood, 

 Illinois. They were discovered by Dr. J. C. 

 Winslow, of Danville, in 1 875. The remains 

 discovered by him were forwarded to Pro- 

 fessor Cope for identification. Later the 

 deposits were thoroughly explored by W. F. 

 E. Gurley, and the specimens collected by 

 him are now preserved (86) in Walker Mu- 

 seum, University of Chicago. In 1907, the 

 writer, while working for the University of 

 Chicago, in exploring the same locality, 

 exhausted the beds so far as they could at 

 that time be uncovered from the landslide 

 which had overwhelmed them. The for- 

 mation in which the bones occur is a soft gray 

 or reddish shale, and it lies without any ap- 

 parent stratigraphic break on shales of Penn- 

 sylvanian age. Below these shales are sev- 

 eral feet of limestone containing invertebrates of typical Pennsylvanian facies. There 

 are indications of at least 3 species of Amphibia in the deposits. Case (86) has in- 

 dicated with doubt a fourth species. The species are: Cricotus heteroclitus Cope, 



9 



UCJ 75 70 



Fig. I. — Map of Upper Pennsylvanian showing land and 

 water conditions under which the Coal Measures 

 amphibian fauna lived. It will be noted that the 

 chief deposits which have furnished amphibian re- 

 mains are on the margins of the heavily shaded 

 areas. (After Schuchert.) 



Explanation of symbols: Lands are white. Water areas 

 are lined. Formation outcrops are black or dotted. 

 Known shore-lines are solid lines; probable ones 

 broken. Vertical lines in middle of continent indi- 

 cate Gulf marine. 



