84 WILLIAMS — ON KANSAX DRIFT IN PENNSYLVANIA. [April 1, 



Jefferson Manuscript Dranglit of the Declaration of Inde- 

 pendence in the Library of the Societ}^" 



B}^ Mr. S, F. Peckham, " The Genesis of Bitumens, as 

 Related to Chemical Geology." 



Pending nominations Nos. 1432 and 1451 to 1457 and 

 new nominations Nos. 1458 to 1464 were read. 



The Society was adjourned by the presiding member. 



NOTES ON KANSAN DRIFT IN PENNSYLVANIA. 



BY PEOF. EDWAKD H. WILLIAMS, JK. 



{Read April 1, 189S.) 



The writer uses the terms Kansan and Wisconsin to represent 

 respectively the furthest ice advance and the first great moraine of 

 recession which was delimited by Lewis and Wright, without 

 accepting the differences in age claimed by some authorities. His 

 work since 1893 has been a study and mapping of the Kansan 

 deposits in this State, and papers have been published from time to 

 time, copies of which have been deposited in the library of this 

 Society. 



At the Buffalo meeting of the American Association for the Ad- 

 vancement of Science, in 1896, the writer presented a few notes on 

 the work of the preceding months and claimed that the ice which 

 covered the northern part of this State oriL>inated at two centres, 

 an eastern and a western, as tiie lithological burden on either side 

 of the apexes of both Kansan and Wisconsin deposits differed 

 widely in character, kinds and amount of crystalline and clastic 

 material. This claim was further substantiated by the fact, shown 

 in the sketch accompanying this paper, that the apex of the earlier 

 line of drift had been overridden by the latter, while, had the latter 

 been a moraine of recession only, there should have been a contin- 

 uous Kansan border. 



To these claims the writer now wishes to add two more. First, 

 that the powers of the two bodies of ice on either side of the apex 

 were unequal, as the eastern Kansan border will average thirty 



