Feb. 19, IS86.J &ol [Branner. 



PROCEEDINGS 



OF THE 



AMERICAN PHILOSOPHICAL SOCIETY, 



HELD AT PHILADELPHIA, FOR PROMOTING USEFUL KNOWLEDGE. 



Vol. XXIII. July, 1886. No. 123. 



The Glaciation of Parts of the Wyoming and Lackawanna Valleys. By 

 John C. Branner, Ph. D. 



{Read before the American Philosophical Society, February 19, 1S86.) 



Prefatory. 



It has long seemed to me that the careful study of limited glaciated 

 areas would add some valuable information to our present knowledge of 

 the subject of continental glaciation. By a limited area I mean one suffi- 

 ciently large to have a varied and well-defined topography, when taken in 

 connection with the surrounding country, and small enough to admit of 

 thorough examination, and of a representation upon the map of details 

 which cannot be admitted into maps of large areas without obscuring the 

 subject instead of throwing light upon it. The Wyoming and Lacka- 

 wanna valleys, with their bordering mountains, form such an area, and 

 the work necessary to make of this region a topographical map of unusual 

 detail gave me an excellent opportunity for making the necessary observa- 

 tions. 



I have hesitated though about presenting observations that would be so 

 much more valuable had they been extended, with the same care and 

 detail, over a wider territory, and especially over the high lands that 

 bound the valley to the north and north-west on one side, and to the east 

 and south-east on the other ; but as I shall, in all probability, have no 

 opportunity for completing the work, and as all knowledge is cumulative, 

 I offer these notes in the hope that others may be induced to add to them, 

 and thus render them more valuable. 



The glacial geology of this region is exceedingly varied and interesting. 

 The Shickshinny end of the basin, on account of its bold and well-defined 

 topography, is particularly so, especially in the study of the ice currents 

 in their relation to topography. In studying the area under consideration; 

 however, I have never lost sight of the fact that I was dealing with a very 

 small portion of the glaciated part of the continent, and with localized 

 parts, localized movements, and localized facts in a continental glacier. 



Although the work done and the explanations offered here are entirely 



PROC. AMER. PHILOS. SOC. XXIII. 123. 2q. PRINTED MARCH 29, 188G. 



