Ithaca Group 



from the name of an epoch to that of a period, and that it in- 

 clude the Chemung and Portage epochs. This suggestion to 

 substitute the name of a local formation not well characfterized 

 paleontologically for one of wide extent with a very distindtive 

 fauna like the Chemung has not met with favor and has been 

 followed by no other writers. 



All recent studies of the Catskill group go to show that it is 

 the stratigraphic equivalent of the Upper Devonian of the cen- 

 tral and western parts of the State. 



In the detailed and careful study of the relations of the Upper 

 Devonian faunas of New York, Prof. H. S. Williams was the 

 leader; and to him more than to any other student, paleontolo- 

 gists are indebted for our present knowledge of these faunas. 

 In the year 1894 he published the results of the study of a sec- 

 tion from Cayuga lake to Bradford county, Pennsylvania. The 

 horizons included in this study are shown in the following sec- 

 tion =*=: — 



Feet. 



XII. Barclay coal bed. 

 XL Pottsville conglomerate. 



X. Mauch Chunk Red shale. V 1000 



IX. Pocono Gray sandstone. 

 Catskill Red sandstone. 



Upper Chemung fauna in Penna. (top at Ulster)... 300 

 Typical Chemung fauna (outcropping in the vicini- 

 ty of State-line, bottom of Chemung Narrows, N. Y. 300 

 Lower Chemung fauna (bottom outcrops at Caroline, 



Danby and Newfield) ■••• 600 



- Upper Portage Sandstones and Shales of H. S. Wil- 

 liams • 600 



f Upper Ithaca 200 



Middle Portage, j Typical Ithaca 100 



(Lower Ithaca 150 



Lower Portage Sandstones and Shales 250 



, Genesee Shales • •• 



3500 



In this study Dr. Williams attempted to discover the associa- 

 tion of the species in faunas and the relation of these to each 

 other. In the Portage rocks at Ithaca two distincft faunas were 

 recognized, — the Cladochonus and Spirifer Icevis, — and the rela- 

 tion of these to those of the Ithaca group was pointed out.f 



* Trans. Am. Inst. Min. Engineers, vol. xvi, p. 945. 

 t Bull. U. S. Geol. Surv., No. 3, p. 11. 



