THE CARBONIFEROUS FISH-FAUNA OF MAZON 

 CREEK, ILLINOIS. 



Of the thousands of fossiliferous ironstone nodules of Coal 

 Measure age, occurring at Mazon Creek, near Morris, in Grundy 

 county, Illinois, only a small percentage afford indications of 

 vertebrate remains, and these consist principally of detached 

 fish-scales. Occasionally, however, complete individuals of 

 fossil fishes, and still more rarely, amphibian skeletons have 

 been brought to light, but all told the number of even tol- 

 erably perfect specimens preserved in different museums is very 

 insignificant. Probably the two finest series of Mazon Creek 

 nodules ever brought together are the Lacoe collection, belong- 

 ing to the United States National Museum in Washington, and 

 the Strong collection, purchased by the late Professor Marsh for 

 the Peabody Museum, at Yale College. Shortly before the 

 decease of Professor Marsh, nearly all of the fossil fishes in the 

 Strong collection were placed by that gentleman in the hands of 

 the writer for study and description ; and more recently some 

 further material has been loaned for the same purpose by Pro- 

 fessor C. E. Beecher, to whom grateful acknowledgments are due. 



Mazon Creek fish-scales have been exhaustively studied by 

 E. D. Cope 1 and O. P. Hay, 2 and the latter has also described a 

 nearly perfect example of a Palaeoniscid fish, named by him 

 Elonichihys hypsilepis. A few other Palaeoniscids and Platysomids 

 have been described by Cope 3 and by Newberry and Worthen; 4 

 and two Acanthodian species have recently been made known by 

 the present writer. 5 These citations complete the literature 

 references on Mazon Creek fishes. In the following paragraphs 



I Proc. Amer. Phil. Soc, Vol. XXXVI (1897), pp. 71-82. 



"Ibid., Vol. XXXIX (1900), pp. 96-120. 



iProc. U. S. Nat. Museum, Vol. XIV (1891), p. 462. 



'•Pal. Illinois, Vol. II (1866), and Vol. IV (1870). 



*Bull. Mus. Comp. Zool., Vol. XXXIX (1902), pp. 93, 94. 



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