The life of the Pleistocene or glacial period as recorded in the deposits laid down by the great ice sheets

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...of which 23 or 92 percent are extinct. The mammalian fauna resembles most closely the fauna of the Equus zone or Sheridan formation described by Osborn. It likewise resembles the fauna of the bone caves of Pennsylvania as well as the Hay Springs fauna of Nebraska and Hay has stated his belief that all of these deposits should be referred to the Aftonian." There is clearly a very close resemblance between the species represented, and particularly between the extinct species, but this would most likely be the case in the first interglacial interval, not only for the reason that the large mammals could find refuge south of the ice sheet, but also because all of the species undoubtedly lived in abundance in the region south of the affected territory, where the environment was possibly but little changed, and formed a reserve fauna which migrated northward as soon as the Aftonian climate became favorable. » Smith. His. Coll., LIX, p. 15. CHAPTER VIII THE KANSAN ICE INVASION AND THE YARMOUTH INTERGLACIAL INTERVAL I. Tm: KANSAN Ics INVASION Following the Aftonian Interglacial interval, climatic conditions again became severe and a second ice sheet, the Kansan, advanced and covered a large portion of the United State (Plate XLVI). East of the 110th meridian the ice sheet extended a short distance south and west of the Missouri River in Montana, the Dakotas, Nebraska, Kansas and The largest known lobe extended southward west of the Mississippi River and the driftless area, spreading entirely over Iowa and entering Nebraska, Kansas, and Missouri, as well as a narrow strip in western Illinois. Another lobe entered Illinois but its extent is not known as it is completely covered by the later Illinoian ice sheet. The Kansan has been definitely located beneath...