CHAPTER VI. 

 THE ILLINOIAN DRIFT SHEET. 



SECTION I. FEATURES ISTEAR THE DRIFT BORDER. 



GENERAL STATEMENT. 



The drift sheet here described appears to be the continuation of the 

 Illinoian sheet so widely displayed in Illinois and western Indiana. It 

 connects directly with that sheet at the reentrant angle in the glacial 

 boundary in south central Indiana. From this reentrant angle eastward 

 across southeastern Indiana, northern Kentucky, and southwestern Ohio its 

 general aspect and relations are similar to those of the Illinoian sheet 

 farther west, and it extends to the limits of glaciation. If the Kansan or 

 earlier sheets of di-ift are present their borders probably lie within the 

 limits of this Illinoian sheet or are so meagerly represented at the edge that 

 they have been unrecognized. 



As already indicated, the Illinoian drift has been identified no farther 

 east than western Holmes County in north-central Ohio, at which point its 

 border passes northward beneath the border of the Wisconsin drift sheet. 



In eastern Pennsylvania and New Jersey a sheet of old drift extends 

 beyond the limits of the Wisconsin, descriptions of which have already been 

 given by Salisbury and others.^ It is barely possible that this sheet is of 



' R. D. Salisbury: Preliminary paper on drift or Pleistocene formations of New Jersey: Kept. 

 Geol. Survey New Jersey, 1891, pp. 102-103. Surface Geology of New Jersey: Rept. Geol. Survey 

 New Jersey, 1892, pp. 151-166. Certain extramorainic drift phenomena of New Jersey: Bull. Geol. 

 Soc. America, Vol. Ill, 1892, pp. 172-182. The older drift in the Delaware Valley: Am. Geologist, 

 Vol. XI, 1893, pp. 360-362. Surface geology; extramorainic drift: Rept. Geol. Survey New Jersey, 

 1893, pp. 73-123. 



E. H. Williams, jr.: Glaciation in Pennsylvania: Science, Vol. XXI, 1893, p. 343. South Moun- 

 tain elaciation: Bulll. Geol. Soc. America, Vol. V, 1894, pp. 13-15. Extramorainic drift between the 

 Delaware and Schuylkill: Bull. Geol. Soc. America, Vol. V, 1894, pp. 281-296. Age of the extra- 

 morainic fringe in eastern Pennsylvania: Am. Jour. Sci., 3d series, Vol. XL VII, 1893, pp. 34-37. 

 Notes on the southern ice limit in eastern Pennsylvania: Am. Jour. Sci., 3d series. Vol. XLIX, 1894, 

 pp. 174-185. 



A. A. Wright: Extramorainic drift in New Jersey: Am. Geologist, Vol. X, 1892, pp. 207-216. 

 Older drift in the Delaware Valley: Am. Geologist, Vol. XI, 1893, pp. 184-186. Limits of the glaciated 

 area in New Jersey: Bull. Geol. Soc. America, Vol. V, 1894, pp. 7-13. 



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