lo Bulletin 6 lo 



In the Ithaca group Williams recognized five faunas — the Lin- 

 gula complanata, Spirifer firnbriatus, Spirifer niesastrialis, Rhyn- 

 chonella e'xhnia and Spirifer mesacostalis. 



The Lingula complanata fauna is a recurrence with a slight 

 modification of the fauna found in the Marcellus shales and the 

 Genesee slate. The presence of this fauna and the recurrent 

 Hamilton species in the Ithaca fauna he considered to be the 

 result of a shifting of faunas, — new conditions and faunas driv- 

 ing the Hamilton and Marcellus faunas out of the area in ques- 

 tion and permitting them to return at intervals, while in some 

 arreas they lived on continuously undisturbed by new conditions. 



Above the Ithaca fauna Williams found a recurrent Portage 

 fauna containing Lunulicardium fragile and Glyptocardia speciosa. 

 The occurrence of these chara(5teristic Portage species above the 

 Ithaca fauna led him to refer it to the Portage group instead 

 of the Chemung where Hall placed it. 



In western New York the studies of Williams and Clarke have 

 thrown much light on the relations of the Upper Devonian 

 faunas. 



In 1883 Prof. Williams published a paper* on a peculiar fauna 

 in Ontario county at the base of the Chemung in what he called 

 the Naples beds. In this fauna he found a majority of forms 

 to be species characteristic of the lyinie Creek beds of Iowa, to- 

 gether with a few species peculiar to the Ithaca and Lime Creek 

 faunas. He therefore correlated the fauna of the Naples beds 

 with the Kinderhook in the West and the Ithaca fauna to the 

 east. 



In Ontario county, Prof. Clarke, as a result of his studies (pub- 

 lished in i885t) found that the Portage group, as originally de- 

 fined by Hall, includes an assemblage of unlike faunas, the lower 

 ones being closely related to the Genesee or Hamilton, while the 

 upper are related to the Chemung. The Cashaqua and Gardeau 

 beds of Hall he includes under the name of the Naples shales. 

 Of the 47 species occurring in the Naples shales, Clarke finds 

 that 34 per cent, occur in the Genesee shale and 19 per cent, in 

 the Hamilton proper, while but 2.1 percent, occur in the Port- 

 age. He concludes, therefore, that the Naples beds should be 

 regarded as constituting the uppermost member of the Hamil- 

 ton, or together with the Genesee, as representing a distincfl 

 geological epoch. 



*Am. Jr. Sci., vol. xxv, p. 97. 

 tBull. U. S. Geol. Surv., No. 16. 



