420 



GEOLOGY. 



The recently revised classification for New York 1 is as follows: 



f Chautauquan. . Chemung (including Catskill) 



Devonic. . . 



Neodevonic. 



Mesodevonic. 



Paleodevonic. . . > 



(Portage beds 

 Genesee shale 

 Tully limestone 



Erian i Hamilton shale 



' \ Marcellus shale 



f Onondaga (Corniferous) limestone 

 Ulsterian ...... •{ Schoharie grit 



[ Esopus grit 



r Oriskanian Oriskany beds 



(Kingston beds 

 Becraft limestone 

 New Scotland beds 

 L Coeymans limestone 



The new classification has an advantage over the old in that the 

 same name is not used to indicate subdivisions of different importance, 

 but the disadvantage of adding to the burden of nomenclature. 

 The term Devonian will be retained instead of Devonic, and Lower, 

 Middle, and Upper Devonian, as synonyms for Paleo-, Meso-, and Neo- 

 Devonic, respectively. The subdivisions in the last two columns 

 are to be regarded as appropriate for the New York region, and those 

 jf the second columns from the right may have wider applicability. 



Recently revised classifications for Maryland 2 and the interior 3 

 are given below. In the latter, Helderberg is excluded. 



Maryland. 

 5. Hampshire = Catskill in part. 

 4. Jennings = Genesee and Portage. 

 3. Romney= Erian. 4 

 2. Oriskany. 

 1. Helderberg = Coeymans. 



Interior. 

 5. Chemung. 



4. Portage (including Genesee). 

 3. Hamilton. 



2. Onondaga (Corniferous). 

 1. Oriskany „ 



The Lower Devonian. 



The Helderbergian series. — The known Helderbergian series is 

 largely confined to the eastern part of North America. It is known (1) 

 in Maine 5 and, beyond the United States, in Gaspe, New Brunswick^ 



1 Clark and Schuchert, Science, Vol. X, 1899. 



2 O'Hara, Maryland Survey, Allegany County. 



3 Hayes and TJlrich, Columbia (Tenn.) folio, 1903. 



4 Prosser, Jour, of Geol., Vol. XII, p. 361. 

 6 Williams, Bull. 165, U. S. Geol. Surv. 



