CHAPTER VII. 



(concluded) 



THE GLACIAL BOUNDARY WEST OF PENNSYLVANIA. 



Through Columbiana county, Ohio, as in the adjoining 

 counties of Pennsylvania, there is, to the south of the heavy 

 accumulations of till, a fringe of thinner glacial deposits from 

 one to three miles wide. Over this margin there are scat- 

 tered evidences of glacial action, consisting of granitic bowl- 

 ders and patches of till here and there upon the highlands, 



* See G. F. Wright, " The Glacial Boundary in Ohio. Indiana, and Ken- 

 tucky," Western Reserve Historical Society ; also " Ohio Geological Report," 

 rol. v, pp. 750-771; T. C. Chamberlin, "Extent, etc., of the Wisconsin Ket- 

 tle Range" ("Transactions of the Wisconsin Academy of Sciences," vol. iv); 

 "Geological Survey of Wisconsin," vols, ii and iii (Madison, 1877-80); "Pre- 

 liminary Paper on the Terminal Moraine of the Second Glacial Epoch " (United 

 States Report); George H. Cook, "Annual Reports for Xew Jersey for 1877, 

 1878"; G. M. Dawson, "On the Superficial Geology of British Columbia" 

 ("Quarterly Journal of the Geological Society, 1878," vol. xxxv, p. 89); J. W. 

 Dawson, "Changes of the Coast-Level in British Columbia*' ("Canadian Natu- 

 ralist," April, 1877); G. K. Gilbert, "On Certain Glacial and Post-Glacial Phe- 

 nomena of the Maumee Valley, Ohio" ("American Journal of Science, 1871." 

 vol. ci, p. 339); C. H. Hitchcock, "Moraines of Xorth America" ("Popular Sci- 

 ence Monthly," 1881) ; Clarence King, " United States Geological Explorations of 

 the Fortieth Parallel," vol. i; " Systematic Geology " (Washington, 1878) ; Lewis 

 and Wright, " Report on the Terminal Moraine in Pennsylvania and Western 

 Xew York, Second Geological Survey of Pennsylvania, Z " ; Warren Upham, 

 " The Xorthern Part of the Connecticut Valley in the Champlain and Terrace 

 Periods" ("American Journal of Science, 1877," vol. cxiv, p. 459); "The For- 

 mation of Cape Cod" ("American Xaturalist, 1879," vol. xiii, pp. 489, 552); 

 "Geological Survey of Xew Hampshire," vol. iii (1878); "Geological and Natu- 

 ral History Survey of Minnesota " (Report for 1879) ; " Terminal Moraines of 

 the Xorth American Ice-Sheet" ("American Journal of Science, 1S79," vol. 

 cxviii, pp. 81, 197); Charles Whittlesey, "Fresh- Water Drift of the Xorthwest- 

 ern States" ("Smithsonian Contributions, 1866," vol. xv); X. H. Winchell. 

 "The Drift Deposits of the Xorthwest" ("Popular Science Monthly," vol. iii, 

 pp. 202, 286); "Geology of Minnesota" (Annual Reports, 1872, etc.). 



*Soe also full lists given in the Appendix. 



