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Browse more than 5,500 book chapters authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.

Filter Total Items: 6152

Trichomoniasis Trichomoniasis

No abstract available.
Authors
R. M. Kocan, C. M. Herman

Aquilapollenites (Rouse) Funkhouser — Selected Rocky Mountain taxa and their stratigraphic ranges Aquilapollenites (Rouse) Funkhouser — Selected Rocky Mountain taxa and their stratigraphic ranges

The genus Aquilapollenites and its type species, A. quadrilobus, are redescribed, and the latter is illustrated. This report summarizes our present information on stratigraphic ranges of selected Rocky Mountain species and varieties of Aquilapollenites. Of the 17 taxa included in this report, 10 are previously named species, 4 are new species, and 3 are new varieties. One species is...
Authors
Bernadine D. Tschudy, Estella B. Leopold

Ground water resources of Iowa Ground water resources of Iowa

No abstract available.
Authors
W. L. Steinhilber, P. J. Horick

Survival and development of lake herring (Coregonus artedii) eggs at various incubation temperatures Survival and development of lake herring (Coregonus artedii) eggs at various incubation temperatures

Lake herring eggs stripped and fertilized from a local stock were incubated in a constant-flow incubator at constant temperatures ranging from 0 to 12.1° C. Rate of development, percentage survival, percentage of abnormal and normal hatching, and length of fry at hatching were determined. The average incubation time from fertilization to 50% hatch varied from 37 days at 9.9-10.3° C to...
Authors
Peter J. Colby, L.T. Brooke

Palynology of the Cretaceous-Tertiary boundary in the northern Rocky Mountain and Mississippi Embayment regions Palynology of the Cretaceous-Tertiary boundary in the northern Rocky Mountain and Mississippi Embayment regions

In both the Rocky Mountain and the Mississippi Embayment regions it is often difficult to distinguish Upper Cretaceous from lower Tertiary rocks on the basis of physical characteristics; the transition can be recognized with relative ease, however, on the basis of abrupt qualitative changes in plant microfossils. Many Cretaceous species vanish and new species appear in the Paleocene. In...
Authors
Robert H. Tschudy

Introduction Introduction

No abstract available.
Authors
Robert M. Kosanke, Aureal T. Cross
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