Page:The Journal of geology (IA journalofgeology21894univers).pdf/169

midst of it; that is, the Ithaca fauna is both below and above it. Again, upon going further west, the same interval is filled by a non-brachiopod marine fauna, i.e., that of the typical Portage group of Genesee valley, and the Ithaca group of Ithaca is in the midst of the corresponding rocks of the Portage, as the Oneonta is in the midst of the Ithaca. This I interpreted, in the paper referred to, as indicating that the succession of faunas was controlled by oscillation of levels during the accumulation of the deposits, the eastern shores rising during the first half of the Portage (of the Genesee valley series) so that, during the particular stage represented by the fossiliferous zone of the Ithaca group, Portage fossils were being accumulated in the Genesee valley sediments, Ithaca fauna at Cayuga lake meridian, and, from Chenango eastward to Oneonta, sands with fresh water Amnigenia and Holoptychius characteristic of the Catskill formation.

THE FORMATIONS OF THE DEVONIAN SYSTEM IN THE APPALACHIAN REGION AND THEIR RELATIONS TO THE TIME-SCALE.

Time Scale.		Formation Scale.
		Genesee River.	Cayuga Lake.	Delaware Co.	Hudson River	Maine.
Eocarboniferous
Neodevonian	${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}}$	Conglomerate	Catskill	Catskill	Catskill	Catskill
		Chemung
			Chemung
				Chemung
			P2	H
		Portage	Ithaca	Oneonta
			P1	H2	H2
		Genesee	Genesee
			Tully
Mesodevonian	${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}}$	Hamilton	Hamilton	Hamilton	Hamilton
		Marcellus	Marcellus
Eodevonian	${\displaystyle \scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}}$	Corniferous	Corniferous	Onondaga
			Onondaga	Schoharie	Schoharie
				Caudagalli	Caudagalli
		Oriskany	Oriskany			Oriskany
				Oriskany	Oriskany
Neosilurian