858 NEW YORK STATE MUSEUM 



of late Siluric faunas were holding the ground on the inner or 

 mediterranean side. The arguments in support of such a barrier 

 in eastern New York during various epochs of Paleozoic time are 

 strong and have been well constructed by the authors referred to. 

 Their hypothesis proves of great service in properly construing 

 the long known and palpable difference in the development of 

 the Paleozoic rocks in eastern New York and in the central and 

 western parts of the State. We are disposed to believe that 

 the complete analyses of the proposition now before us concern- 

 ing the value of the Coralline limestone and fauna will throw 

 important light on the existence and influence of such possible 

 land barrier during late Siluric time. 



We have above and previously used the expression, " Oobleskill 

 limestone," as an alternative name for this formation, in view of 

 the fact that stratigraphic names seem to meet modern require- 

 ments only if designated by geographic terms. The term " Coral- 

 line " is unfortunate in many respects ; it originally had reference 

 to the abundance of corals in the rock, but the word is now used 

 with a different signification, and, while it has no geographic 

 value, it has neither the biologic importance which such term 

 should carry. The Cobleskill presents the best sections of the 

 formation to be found in the region of its typical exposures. 



Mr C. A. Hartnagel, who has been specially concerned with 

 the study of this problem, communicates the following account 

 of his field operations: 



Work on the Cobleskill formation. This report is a brief 

 account of the field work during the greater parts of the 

 months of August and September, on the Cobleskill forma- 

 tion. For convenience the region studied is here considered 

 in three sections. First, that extending from Gallupville, 

 Schoharie co., west and northwest through Shutter's Corners, 

 Schoharie, Howes Cave, Central Bridge, Grovenor's Corners, Car- 

 lisle, Sharon Springs and the section to the north and northwest 

 of Cherry Valley in Otsego and Herkimer counties. Second, that 

 section in Albany county, along the northern and eastern ends of 

 the Helderberg plateau, extending from Altamont, and including 

 the Indian Ladder and New Salem sections, to South Bethlehem. 

 Third, the section extending from Catskill in Greene county, south 



