BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 5, pp. 281-296, PLS. 9-11 MARCH 14, 1894 



EXTRAMORAINIC DRIFT BETWEEN THE DELAWARE AND 



THE SCHUYLKILL 



BY EDWARD H. WILLIAMS, JUNIOR 



{Read before the Society December 29, 1893) 



CONTENTS 



Page 



Review of previous Investigations 281 



Area Studied 282 



T< )pog'raphic Features 282 



River Systems of the Region 28l> 



Rocks of the Region. ... 285 



Glacial Deposits. 286 



Tiie Fringe 28() 



The Packer Clay 28(5 



Drumlins, Karnes and other glacial Phenomena 289 



The Till and its Age 290 



Tlie underlying Rocks 294 



Preglacial Surfaces 294 



Summarv 296 



Review of [previous Investigations. 



The part of Pennsylvania described in this paper was allotted in the 

 recent state survey to Professor Frederick Prime, junior, and in 1874 he 

 made his first report (D), on page 62 of which the state geologist notes 

 that Professor Prime " has wisely said nothing in his report about his 

 ol)Scrvations on supposed glacial drift." He further notes that Mr 

 Chance found, in the spring of 1875, a moraine behind the Lehigh Gap. 

 In Professor Prime's second report, DD, in 1878, he devotes chapter xxiv 

 to " The Glacial Epoch," and states that his efforts to follow the lines of 

 bowlders was " a hopeless one and had to be abandoned." He further 

 notes the finding of vegetable remains in what must have been sub- 

 glacial till, and characterizes the filling of a great range of limonite mines 

 as " drift." In his third report, D 3, volume i, also of 1878, he seems to 



XXXIX-Bui,L. Geoi-. Soc. Am., Vol. 5, 1893. (281) 



