STATE GEOLOGIC MAP OF 1901 



15 



the state, the Hall map of 1894 being used where no information 

 of later date was obtainable. 



In the Mohawk valley the mapping of the Paleozoic is based 

 largely on Darton's work under the direction of the late James 

 Hall. The boundary between the Cambrian and the Silurian, 

 north of the Adirondacks, is to be credited to Cushing. White's 

 mapping, revised in some places by Eckel, was used for the 

 Lower Silurian formations in most of Oneida county and in 

 parts of Herkimer and Lewis. 



The Upper Devonian and the Carboniferous 



The mapping of the formations above the Onondaga on the 

 present edition of the geologic map is based, east of the Chen- 

 ango valley, on the work of Prosser, except in Albany county, 

 where Darton's boundaries have been used. West of the Chen- 

 ango valley it is based mainly on recent published and unpub- 

 lished work of Dr John M.Clarke, aided by Luther in some areas, 

 the portion not thus recently revised being copied from the Hall 

 map of 1894. The position of the Tully limestone, first mapped 

 by S. G. Williams, has been revised by Luther throughout most 

 of its length and by Eckel in that portion appearing on the Ovid 

 atlas sheet. 



The Carboniferous outliers in the southwestern part of the 

 state are as mapped, in manuscript, by Clarke after Randall, 

 but are not considered by Dr Clarke to be very reliably deter- 

 mined. 



Triassic to Pleistocene 



The Triassic sandstone and diabase of Rockland county are 

 as mapped by Kummel. The pre-Pleistocene boundaries on 

 Staten Island are based on the mapping of Hollick; the Pleisto- 

 cene of Staten Island and Long Island are from the mapping of 

 Woodworth and Woodman. Their respective areas were sep- 

 arated by the meridian of 73° 30', Woodworth mapping all west 

 and Woodman all east of that line. The continuation of the 

 moraine across New Jersey and Pennsylvania is credited to- 

 Salisbury and Lewis. 



