THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE IV. VOL. IV. 



No. XII.— DECEMBER, 1897. 



OI^IOiniTJ^Xj .A.S,TICLES. 



I. — Glacial Geology of Western New York.^ 



By Professor Herman Le Eoy Eairchild, B.Sc, 

 Secretary of the Geological Society of America. 

 (WITH A MAP, PLATE XXI.) 

 Table op Contents. 



Physical Features : Stratigraphy, Topography, Hydi'ography, and Pre - Glacial 



Topography and Drainage. 

 Ice Invasion : Directions of Flow and Thickness of Ice-cap. 

 Glacial Deposits : General Drift Sheet, Drumlins, Moraines. 

 Glacio-Aqueous Deposits : Eskers, Kames. 

 Glacial Lakes : Primitive and Smaller Local Lakes ; Larger Local Lakes ; Pre- 



Laurentian Lakes — Lake Warren, Lake (unnamed ; Geneva Beach), Lake 



Iroquois. 

 Morainal Lakes. Channels of Glacial Drainage. Post-Glacial Stream Erosion. 



Physical Features. 



StratigrapJiy. 



n^HE area herein described is that part of New York State Ijing 

 i south of Lake Ontario, and west of longitude 76°. The 

 dimensions of the area ai'e, approximately, 95 miles north and south 

 and 155 miles east and west, or nearly 15,000 square miles. The 

 rocks ^ are shales, sandstones, and limestones of the Upper Silurian 

 and Devonian systems. The strike is nearly east and west, with 

 a southward dip averaging perhaps 50 feet to the mile. The lime- 

 stones are contained almost entirely in the lower strata and outcrop 

 in the northern belt, where the surface has the lower altitude. The 

 more arenaceous rocks form the elevated plateau of the middle and 

 southern belts. 



Topography. 



The present surface configuration is a complex result of several 

 agencies, which naay be succinctly grouped as follows : — 



' A paper read at the Toronto Meeting of the British Association, August, 1897. 



* The stratigraphy is fully described in Dr. James Hall's Eeport, " J^atural 

 History of New York " : Eeport on the Fourth Geological District, by James Hall, 

 Albany, 1850. 



decade it. VOL. IV. — NO. XII. 34 



