186 THE DEVONIAN AND CARBONIFEROUS. [bull. 80 



Since the writing of that report, the author had discovered several 

 microscopic forms of vegetation occurring in these bituminous shales 

 in great abundance. Dr. Dawson had previously observed these 

 bodies, and recognized them as the spore cases of some lycopodiaceous 

 plant, and named them Sporangites Huronensis. 1 



The author supposes that the great accumulations of gas and oil tbat 

 have been found in the Devonian and Subcarboniferous formations of 

 Pennsylvania, West Virginia, and Ohio are to be traced to the further 

 distillation or decomposition of the bituminous matter, particularly the 

 spore cases origiu ally deposited with these black shales, a theory which 

 was «first outlined by Newberry, 2 although the presence of the spore 

 cases was then unknown. To the spore cases the author would attrib- 

 ute the chief supply of bituminous matter. 



In 1883 H. S. Williams 3 reported the discovery of a fauna in the 

 midst of the upper Devonian rocks of New York, having a decided 

 carboniferous aspect, but closely related to a fauna heretofore known 

 in America only at the base of the Mississippian series in Iowa. 



At the base of the Chemung group at Ithaca and High Point, Naples* 

 New York, the author found a fauna which is strikingly similar to a 

 fauna found at Lime Oreek, near Rockford, Iowa. Although the gen- 

 eral aspect of the fauna is Carboniferous, yet the occurrence of several 

 of the species in the Cbemuug rocks requires consideration. The Lime 

 Creek fauna was ascribed to the Hamilton group in 1858 by James 

 Hall, but it was afterwards, in 1873, by him and by R. P. Whitfield 

 referred to the " Chemung group." 



By a close comparison of the faunas and minute and accurate exam- 

 ination of the specific relations of these faunas to each other, the author 

 is convinced that the deposits of Lime Creek, Iowa, and all deposits 

 carrying a like fauna, are not Lower Carboniferous, but are " geological 

 equivalents of the Chemung of the East." 



Mr. S. Calvin 4 took exception to the conclusions of Williams concern- 

 ing the " strikingly Carboniferous aspect of the Lime Creek fauna," 

 claiming, after an examination of the fossils, that they exhibit rather 

 a Devonian and Silurian aspect, and Williams 5 replied. 



The importance of the discovery consisted in the recognition of traces 

 of the fauna, which is Carboniferous in its aspect, in America before the 

 close of the Devonian in New York. The recognition of the same in 

 Iowa proved the appearance there of a fauna of true upper Devonian 

 age; that is, more recent than the Hamilton and older than the typical 

 Kinderhook faunas of the Mississippian area. 



1 On spore cases in coals ; by J. W.Dawson, LL. D., F. It. S. Am. Jour. Sci., 3d ser., vol. I, pp. 256-263 



2 Agricultural Report of Ohio in 1869. 



3 Williams, Henry S. : On a remarkable fauna at the base of the Cbemung group in New York. Am. 

 Jour. Sci., 3d ser., vol. 25, pp. 97-104. 



4 Calvin, S. : On the fauna found at Lime Creek, Iowa, and its relation to other geological faunas. 

 Am. Jour. Sci., 3d ser., vol. 25, 1883, pp. 432-436. 



* Williams. Henry S. : Equivalency of the Lime Creek beds of Iowa. Am. Jour. Sci., 3d ser., voL 

 25, 1883, p. 311. 





