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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
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Correlations and problems in belt series stratigraphy, Northern idaho and western Montana
A continuous strip of geologic maps has recently been completed along the Idaho-Montana state line between Clark Fork, Idaho, and Superior, Montana. New stratigraphic and petrographic information provides the basis for stratigraphic correlations and for the interpretation of facies changes in this part of the basin of deposition of the Precambrian Belt Series. Identification of facies changes is a
Authors
J. E. Harrison, A.B. Campbell
Relation between the crystal content and the chemical composition of welded tuffs
No abstract available.
Authors
Donald W. Peterson, Ralph Jackson Roberts
Ash-flow problems — a synthesis based on field and laboratory studies
No abstract available.
Authors
Robert L. Smith
Insecticides: effects on cutthroat trout of repeated exposure to DDT
Cutthroat trout were periodically exposed to p, pp-DDT, in acetone solution or in the food. Excessive mortality occurred only in lots treated with high concentrations of DDT, probably as a result of decreased resistance to nonspecific stressors. Surviving fish in these lots were significantly larger than those in the control lot, or in the lots treated with low concentrations of DDT. The number an
Authors
Don Allison, Burton J. Kallman, Oliver B. Cope, Charles C. Van Valin
Early pennsylvanian currents in the southern Appalachian Mountains
Measurement of more than 1200 cross-beds in lower Pennsylvanian sandstones of the southern Appalachian Mountains reveals a broad pattern of sediment transport to the southwest and west. Most of the sand appears to have been derived from the east and to have moved south-westward parallel to the axis of the Appalachian geosyncline. The pattern has a similar alignment to that in the Illinois basin, b
Authors
J. Schlee
Water-level trends in key observation well May-July 1963 (Abstracted from U. S. Geological Survey “Water Resources Review”)
No abstract available.
Authors
S. W. West
Television — A new tool for the ground‐water geologist
The television camera has become a tool of the ground‐water geologist, enabling him to examine visually the inside of a well deep below the land surface. Using the camera, the rocks can be viewed in place. Of great importance to the ground‐water studies in coastal Georgia, the camera enables the geologist to see the important water‐bearing zones in a limestone aquifer, and to recognize cracks and
Authors
J.T. Callahan, R. L. Wait, M.J. McCollum
Recharge rates of principal aquifers in Lake County, Indiana
The upper 350 to 400 feet of rocks underlying Lake County, Indiana, form a single but complex hydrologic system. The rock units composing this system consist (in ascending order) of dolomite, clay till (unit 4), glaciofluvial sand (unit 3), clay till (unit 2), and lacustrine sand, silt, and clay (unit 1). The dolomite and unit 3 form the principal aquifers and the clay tills, units 4 and 2, the co
Authors
J.S. Rosenshein
Reductive dechlorination of DDT to DDD by yeast
Labeled DDD [ 1,1-dichlor-o-2,2-bis(p-chlorophenyl)-ethane] was formed from C14-labeled DDT in the presence of yeast. The formation of DDD from DDE [1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene] was not observed, indicating that a reductive dechlorination of DDT occurs.
Authors
Burton J. Kallman, Austin K. Andrews
Sinuosity of alluvial rivers on the great plains
Data on the morphologic and sediment characteristics of stable alluvial rivers of the Great Plains were collected at 50 cross sections. The channel patterns of these rivers were classified into five types: tortuous, irregular, regular, transitional, and straight. Because no clear demarcation existed between each of the types, the pattern of the rivers was described by sinuosity, a ratio of channel
Authors
S. A. Schumm
Origin of precambrian iron formations
A statistical study of the chemical composition of the Precambrian iron formations of the Canadian Shield affords a new approach to the origin of these unusual formations. The average total iron content of 2,200 samples from the literature and from unpublished mining company analyses is 26.7 percent Fe. The average Fe content for 16 iron formations in the United States and Canada ranges from 24.5
Authors
H. Lepp, S. S. Goldich
Origin of some intermittent ponds on quartzite ridges in western North Carolina
Several intermittent ponds and closed depressions as much as 200 feet wide occur on the crests of ridges in gently dipping Cambrian(?) quartzites in the southeastern foothills of the Blue Ridge Mountains near Morganton, North Carolina. The unconsolidated fill and debris in the ponds consists of clayey sand and saprolite with accessory minerals that could have been derived entirely from the quartzi
Authors
John C. Reed, Bruce H. Bryant, John T. Hack