8 CONTENTS. 



Chapter IV. — The drift border or glacial boundary — Continued. Page. 



Section II. The border of the Illinoian drift 222 



Section III. Tlie border of the Wisconsin drift 226 



Chapter V. — The oldest drift (Kansan ok pre-Kansan) 228 



General statement 228 



Description of the drift 228 



Amount of erosion 235 



Character of the outwash 237 



Tionesta Valley 238 



Lower Allegheny Valley 239 



Upper Ohio Valley 249 



Beaver Valley 251 



Chapter VI. — The Illinoian drift sheet 253 



Section I. Features near the drift border 253 



General statement 253 



Topographic expression of the drift border 254 



Structure of the drift border 261 



Section II. Qeneral aspects of the Illinoian drift sheet 270 



Section III. Character of the outwash 285 



General statement 285 



Sandy Creek Valley 285 



Tuscarawas and tributaries 286 



Licking-Muskingum Valley 286 



Hocking Valley. ... - 288 



Salt Creek Valley 289 



Scioto Valley 289 



Middle and Lower Ohio valleys 290 



Chapter VII. — The Sangamon soil and weathered zone 292 



Chapter VIII. — The loess and associated silts 295 



General statement 295 



Distribution 295 



Thickness of the silt 296 



Characteristics 297 



Color 297 



Texture 297 



Chemical constitution 298 



Mineralogical constitution 298 



Probable lowan age L ., 298 



Mode of deposition 299 



Chapter IX. — The Peorian or post-loessial soil and weathered zone (Toronto formation?) . 302 



Chapter X. — The early Wisconsin drift 304 



General statement 304 



Section I. Early Wisconsin drift of the Miami lobe 304 



The outer or Hartwell moraine 304 



Distribution 304 



Relief 307 



Range in altitude 307 



Topography 308 



Structure and thickness of the drift 312 



Bowlders 325 



Strife.- 326 



Inner border district 328 



Topography 328 



Structure of the drift 330 



Character of the outwash 834 



