14 Bulletin 6 14 



Hamilton in the Chenango valley is followed by beds bearing 

 an Ithaca fauna, though these may be the stratigraphic equiva- 

 lents of the Portage of the western secftions. 



More recently Prof. J. M. Clarke has studied the fossiliferous 

 beds below the Oneonta sandstone in the Chenango valley. In 

 the western part of Chenango county Prof. Clarke found the Spi- 

 rifer mesastrialis fauna lying unquestionably above the Genesee 

 shales. Where the Genesee and Tully formations in the Che- 

 nango valley and the eastern part of the region are absent Clarke 

 makes the presence of Spirifer mesastrialis the index of the ap- 

 pearance of the supra-Hamilton fauna. The Portage fauna, ac- 

 cording to Clarke, is entirely absent from the Chenango valley. 

 There is, he states,* not a single species common to the typical 

 Portage of the Genesee sedlion and the Ithaca fauna of the Che- 

 nango valley. 



The Cayuga secftion, he thinks, represents the mingling of 

 those two faunas, the Portage from the west and the Ithaca 

 fauna from the east. 



The immediate successor of the typical Hamilton fauna in 

 this region represents a more perfect and normal development of 

 the Ithaca group fauna, Prof. Clarke thinks,! than is to be found 

 in any of the sedlions to the west. Overlying the Ithaca group 

 of this region are Oneonta flags and shales. These Oneonta 

 beds Clarke considers to be the equivalent of the typical western 

 Portage. The principal evidence given for this correlation is 

 the occurrence of peculiar concretions found in both formations. 



The first diagrammatic presentation of the relations of the Up- 

 per Devonian faunas, based on the view that some of them were 

 local faunas imperfe(5lly developed or entirely absent from some 

 of the secftions, was a series of sedlions of the Upper Devonian 

 published by Prof. Williams in 1886. J - 



All of the paleontologists who have since studied the New 

 York Devonian have reached similar views as to the local de- 

 velopment of the faunas. 



Fig. I, republished from Prof. Clarke's Report § on the Che- 

 nango valley, represents probably as accurately as our present 

 knowledge will permit the relations of the Upper Devonian 

 faunas in the eastern, central and western parts of the State. 



*i3th Ann'l Rep't State Geol. of N. Y., p. 555. 



t Ibid. 



JProc. Am. Assoc. Adv. Sci., vol. xxxiv. 



\ 13th Ann'l Rep't State Geol. of N. Y., p. 556. 



