IOWA ACADEMY OF SCIENCES. 121 



PLEUROPTYX IN THE IOWA COAL MEASURES. 



BY J. A. UDDEN. 



At a horizon of some hundred feet above the base of the 

 Coal Measures in Fairfield township in Jefferson county 

 is a seam of a concretionary limestone varying from two 

 to five feet in thickness. It crops out on the hillside in a 

 creek that follows the south side of the abandoned embank- 

 ment of the Chicago, Burlington & Quincy railroad, where 

 this leaves the new line, about a mile and a half west of 

 the city of Fairfield. The ledge has been quarried in 

 several places close to the line of the old road, where some 

 pits are still seen. On this limestone lies a black, fissile 

 bituminons shale, lumps of which are seen in the old pits. 

 Last summer the writer found in one of these lumps a 

 bone which he thought might be a phalanx of some 

 early batrachian. This was submitted to Prof. C. R. East- 

 man of the Museum of Comparative Zoology, who identified 

 it as belonging to Pleuroptyx clavatiis Cope, discovered in 

 the Coal Measures of Ohio. In the lump of shale which 

 contained this bone some small enamelled rhomboidal 

 scales and a few small conical teeth were also observed, and 

 associated with these were some slender and polished bony 

 spines and impressions of numerous small ostracods. The 

 abundance of vertebrate remains was confined to a single 

 lump of the shale, but it suggests that the locality might 

 deserve a more thorough exploration. 



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