THE DELAWARE LIMESTONE 423 



A further elaboration of this work by Dr. Kindle was later pub- 

 lished in an Indiana Report which contained an account of the Devo- 

 nian stratigraphy of Indiana, together with descriptions and figures 

 of its fossils. Dr. Kindle's conclusions regarding the correlation 

 of Devonian limestones of Indiana are stated as follows in this report : 



The problem of the correlation of the Devonian limestones with the New 

 York scale is much more difficult for some parts of the Indiana province than for 

 others. In the vicinity of the Falls of the Ohio we find two quite distinct and 

 well-marked faunas. These are the Spirifer granulosus and the Spirijer acumin- 

 atus faunas, and represent respectively the Hamilton and Corniferous faunas of 

 New York. Near the Falls of the Ohio, the Sellersburg beds, and the leffersonville 

 limestone, which carry these faunas, are sharply differentiated lithologically, the 

 leffersonville limestone being a nearly pure limestone, and representing clear 

 water conditions during its deposition, while the Sellersburg beds are composed 

 of an impure argillaceous limestone. In the northern part of the southern Indiana 

 area these two formations cease to be sharply differentiated lithologically, and 

 merge into each other in a limestone which is neither so pure as the leffersonville 

 limestone nor so argillaceous as the Sellersburg beds near the Falls. Associated 

 with the loss of individuality of these two formations occurs a mingling of their 

 two faunas which renders them indistinguishable as separate faunas. 



In the Wabash area the faunas of the Devonian limestone are even more 

 distinct than that at the Falls of the Ohio. In the lower one Spirifer acuminatus 

 is an abundant fossil, and the fauna does not differ greatly from that in the leffer- 

 sonville limestone at the Falls of the Ohio. The upper fauna is a distinctly 

 Hamilton fauna, but entirely different from the Hamilton fauna of southern 

 Indiana. 1 



At an early date Hamilton fossils were identified by Professor 

 Alexander Winchell from the northern part of the Lower Peninsula 

 of Michigan and the rocks referred to the Hamilton group. In 

 1870 he named it the " Little Traverse group," 2 which in 1895 was 

 shortened by Dr. Lane to the "Traverse group." 3 The southern 

 part of the state is so heavily mantled by drift that formerly it was 

 not known whether the formation occurred there or not; but later 

 study of well sections has shown its presence with a thickness of about 

 eighty feet. On a recent geological map of the Lower Peninsula 

 the formation is shown crossing Monroe and Lenawee Counties 



1 Twenty-fifth Annual Report of the Department of Geology and Natural Resources 

 of Indiana (1900), p. 570. 



2 Report of Progress, State Geological Survey of Michigan, p. 28. 



3 Geological Survey of Michigan, Vol. V, Part II, p. 24. 



