xii LIFE OF THE PLEISTOCENE 



5. South Dakota 235 



6. Montana 237 



7. Minnesota 238 



8. Wisconsin 239 



9. Illinois 239 



10. Canada 240 



III. Systematic Catalog of the Biota of the Aftonian Interval 241 



IV. Summary 343 



Chapter VIII. The Kansan Ice Invasion and the Yarmouth Interglacial Interval 



I. The Kansan Ice Invasion 246 



II. The Yarmouth Interglacial Interval 246 



i. The Yarmouth Soil and Weathered Zone; Typical Exposures 247 



ii. Distribution of the Yarmouth Biota 248 



1. Iowa 248 



a. Post-Kansan Loess 251 



b. Vertebrate Animals 258 



2. Nebraska '. 259 



The Loess 259 



3. South Dakota 260 



4. Minnesota 262 



5. Wisconsin 265 



6. Missouri 266 



7. Kansas 269 



8. Illinois 269 



a. Silveria Formation 270 



b. Loess 271 



9. Indiana 272 



10. Ohio 276 



11. Canada 278 



12. Alaska 279 



in. Systematic Catalog of the Biota of the Yarmouth Interval 280 



iv. Summary 283 



Chapter IX. The Illinoian Ice Invasion and the Sangamon Interglacial Interval 



I. The Illinoian Ice Invasion 285 



II. The Sangamon Interglacial Stage 285 



A. The Sangamon Soil and Weathered Zone; Typical Exposures 285 



B. Distribution of the Sangamon Biota 286 



1. Iowa 286 



2. Illinois ■. . . . 289 



a. Deposits of Fluviatile Origin 289 



b. Old Soil Horizons 290 



c. Florencia Formation 294 



d. Illinoian Loess 296 



e. Vertebrates 298 



3. Indiana 301 



a. Old Soils 301 



b. Loess 306 



c. Mammalian Fauna 309 



