no Bulletin 12 238 



stone is pretty generally wanting or verj' thin in Kentucky. The 

 Sellersburg beds and their fauna have not been seen at all south 

 of lyouisville. 



The preceding review of the history of the attempt to correlate 

 the Devonian of Indiana and Kentucky with the New York De- 

 vonian has shown that the difficulties encountered were chiefly in 

 connecftion with determining the equivalents of the faunas above 

 the Corniferous. The Corniferous fauna of New York suffers no 

 very important modifications in its western extension. The large 

 number of species common to the fanuas of the Corniferous lime- 

 stone of New York and the Jeffersonville limestone, especially 

 among the corals, leaves no doubt as to the equivalence of the 

 two faunas. One of the most abundant and charadleristic species 

 of this fauna in Indiana and Kentucky is Spirifer acuminatus . 

 It is proposed to designate this fauna as the Spirifer aat^ninatus 

 zone of the Kodevonian. 



In southern Indiana we find in the Sellersburg beds a fauna 

 containing many of the most charadleristic species of the Hamil- 

 ton of New York. Among the characteristic New York Hamil- 

 ton Brachiopods which occur in these beds and which are un- 

 known in the Corniferous may be mentioned Spirifer granulosus, 

 Tropidoleptus carinatus, Chonetes coro7iahis, and Pentatnerella pa- 

 vilionensis. Of the lyamellibranchs which are abundant in the 

 New York Hamilton we have in the Sellersburg beds Pterinea 

 flabella, Modiomorpha conce7itrica , and Aviculope^len princips. 

 Many other species occur in these beds which are common both 

 to the Hamilton and Corniferous of New York. In southern 

 Indiana this fauna is not mingled with the Corniferous, as was 

 once supposed, but occurs above that fauna in the Sellersburg 

 beds. The presence in it of such charadleristic Hamilton fossils 

 as those mentioned seems to leave no doubt of its equivalence to 

 the New York Hamilton. This fauna may be designated as the 

 Spirifer granuliferus zone of the Mesodevonian. 



The New Albany shale has offered a more difficult problem in 

 correlation than has either of the other Devonian formations. 

 When the first attempts were made to correlate it with the New 

 York scale its known fauna was limited to one or two Lingulce. 

 The Hamilton fauna at its base had not been recognized and the 

 formation was correlated mainly on stratigraphic grounds with 

 the Marcellus. 



