Early Pleistocene pre-glacial and glacial rocks and faunas of north-central Nebraska. Bulletin of the AMNH ; v. 148, article 1
Supplemental Materials
Date
1972
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Publisher
New York : [American Museum of Natural History]
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Abstract
"A study of the early Pleistocene rocks of the non-glaciated region of north-central Nebraska shows that a paleovalley fill (Keim Formation, new name) that contained the Sand Draw local fauna was preglacial. The stratigraphic position of the overlying Long Pine Formation, new name, is significant because it is the first evidence of a fluvioglacial outwash in the area. Two later sets of deposits overlie the Long Pine formation: Duffy and Pettijohn formations, new names. The source of the gravel in the Long Pine Formation has been a matter of conjecture, some geologists believing it to be the Black Hills, and others the Rocky Mountains. Supporting evidence for either provenience is lacking. Devonian fossils in the Long Pine Gravel indicate that the source was to the north-northeast near Lake Winnepegosis in Manitoba. The Sand Draw local fauna, previously considered Nebraskan (first continental glacier) or Aftonian (first interstadial), correlates with other Blancan faunas, and is the most diverse and northern known of Blancan time. The following groups comprise the fauna: 42 taxa of molluscs, 14 taxa of ostracodes, 10 taxa of fishes (Chaenobryttus serratus, new species), four taxa of amphibians, 14 taxa of reptiles (Geochelone oelrichi, new species), at least 10 taxa of birds, and 35 taxa of mammals. The mammalian fauna has these new forms: a shrew, Planisorex dixonensis, new genus; four rodents, Spermophilus boothi, new species; Spermophilus meltoni, new species; Ophiomys magilli, new species; Ophiomys fricki, new species; and a mustelid, Buisnictis burrowsi, new species. Some of these fossils indicate that the early Pleistocene climate was warmer than the present one, sub-humid, with evapo-transpiration about equal to average annual precipitation. Presence of the large land tortoise, Geochelone, is evidence that the temperature seldom, if ever, dropped below 0°C. Pollen from the Keim Formation is definaitely not of glacial type"--P. 11.
Description
148 p., [2] folded leaves of plates : ill., maps ; 27 cm.
Includes bibliographical references (p. 136-148).
Geology / Morris F. Skinner -- Systematics -- Analysis of ostracodes from the Sand Draw faunal localities / E.D. Gutentag -- The Sand Draw fish fauna / G.R. Smith and J.G. Lundberg -- Amphibians and reptiles / J. Alan Holman -- Class Aves / J. Alan Feduccia and Pat Vickers Rich -- Class Mammalia / Claude W. Hibbard -- Sand Draw local fauna : correlation, age, and paleoecology / Claude W. Hibbard.
Includes bibliographical references (p. 136-148).
Geology / Morris F. Skinner -- Systematics -- Analysis of ostracodes from the Sand Draw faunal localities / E.D. Gutentag -- The Sand Draw fish fauna / G.R. Smith and J.G. Lundberg -- Amphibians and reptiles / J. Alan Holman -- Class Aves / J. Alan Feduccia and Pat Vickers Rich -- Class Mammalia / Claude W. Hibbard -- Sand Draw local fauna : correlation, age, and paleoecology / Claude W. Hibbard.
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