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Gold, silver, copper, and lead-bearing veins, non-radially zoned, occur just beyond the southern and western margins of the Searchlight, Nevada, quartz monzonite stock. Seven samples of the quartz monzonite and purified individual constituent minerals of the rock, representing apophyses and marginal and interior parts of the intrusive mass, were analyzed petrographically...

A pollen diagram from Kirchner Marsh, southeastern Minnesota, records a continuous vegetation sequence from the time of Late Wisconsin ice retreat from the region. The late-glacial and early postglacial portions of the diagram are correlated with a radiocarbon-dated diagram from Madelia, Minnesota. Both diagrams show a series of maxima of...

No abstract available....

No abstract available. ...

In natural scapolites the cell dimension a shows a regular increase from marialite to meionite composition, while c remains constant. Both a and c of synthetic meionite are larger than the corresponding dimensions of synthetic marialite. The cell volume of both natural and synthetic scapolites is a nearly linear function of composition. Variations in cell...

Tetraethyl lead is a normal constituent of vegetation growing along our highways. Washed grass near Denver contained 3000 ppm (in ash) near major intersections and > 50 ppm for 500 feet downwind. Vegetables grown within 25 feet of a road in upstate New York and western Maryland averaged 80 to...

No abstract available....

During early Late Cretaceous the area of the northern Mississippi Embayment was occupied by a structural and topographic dome standing nearly 1000 feet above sea level. Rocks as old as Cambrian were exposed on its crest. Downwarping of the dome, which commenced in Late Cretaceous time, resulted in the development of the Mississippi Embayment syncline, now filled...

An investigation of some aeromagnetic anomalies in north-central Montana shows that remanent magnetization is the dominant factor in anomalies over some rocks and a contributing factor in anomalies over others. In volcanic rocks, remanence is commonly south-seeking down and has an intensity approximately ten times the induced intensity of magnetization. Remanence is shown to be...

A trend toward increasing use of test drilling and subsurface exploration is resulting in a decreasing reliance on human experience in coping with problems in hydrogeology. Application of "observation and inference" and discreet abstraction of readily available data will solve more problems than is now realized. ...

The name jasperoid has been applied to rocks that consist mainly of silica and that have formed by replacement. This paper considers only those jasperoids formed by replacement of limestone. Major problems involved in the origin of such jasperoid include: source of the silica; nature of solutions that dissolve, transport, and precipitate silica; and...

No abstract available....

This article discusses the results of a controlled field testing program, which indicated that definite hydraulic and other advantages may be gained from induced recharging as practiced at Kalamazoo, Michigan. Results include the following: water levels and artesian pressures can be maintained at high stages, the results are lower pumping...

In 1961 a 1000-foot drill hole near Harwich on Cape Cod, Massachusetts, penetrated 435 feet of Pleistocene deposits above 50 to 60 feet of crystalline limestone and phyllitic schist, and more than 500 feet of phyllitic schist with abundant quartz veins. Similar rock is known in the Pennsylvanian and Precambrian...

In the Balmat area in northern New York, tabular deposits of sulfide minerals parallel the layering in folded, siliceous magnesian marbles of a metamorphic complex commonly referred to as the Precambrian Granville Series. Sphalerite, pyrite, and, locally, pyrrhotite and galena have replaced the carbonate minerals in parts of the marble units. The contacts...

No abstract available....

No abstract available....

A statistical analysis is made of the sequences of annual tree ring widths and indices. The expected value of growth during any year is shown to be proportional to the standard deviation of the growth, so that the coefficient of variation is a measure of the sensitivity of the growth of a <span...

Precise measurements of fluctuations of ground-water temperature based on monthly readings in shallow glacial-outwash aquifers may be used to study ground-water movement and recharge. An increase in storage in the shallow basin of Okabena Lake, Worthington, Minnesota, permits the water to cover a much larger area and probably increases the opportunity for infiltration of...

A prominent aeromagnetic anomaly in Randolph County, Indiana, suggests the existence of a dikelike structure within the Precambrian basement rocks. Because of the ambiguity inherent in magnetic interpretation, a unique solution for the parameters involved (depth of burial, geometric configuration, and magnetic susceptibility of the mass producing the anomaly) is impossible. However, if one of the <span...

In 1958 the U.S. Geological Survey and the U.S. Weather Bureau jointly conducted a study of tritium fallout distribution over the continental United States, Alaska, and Puerto Rico. The observation period extended from early April to late July in most areas. While this was insufficient to cover the decay side of the...

A contour map of the Precambrian surface for a part of northeastern New Mexico has been prepared from aeromagnetic, gravity, and drill-hole data. The area extends approximately from the Colorado border south to latitude34° N., and from the foothills of the Sangre de Cristo Mountains east to longitude 104° W. Thirty-seven...

Some recent paleogeographic maps indicate that central Idaho was part of a major geosyncline throughout Paleozoic time. This concept, apparently based on thick marine accumulations far apart on the margins of the region, is inconsistent with field data. Within the area of the Idaho batholith, Permian(?) volcanic rocks rest either on batholithic rocks...

In a study of the relationship of magnetic anomalies to the magnetite content and structure of layered Precambrian iron-formations, the effective induced and remanent magnetizations of the Biwabik iron-formation were determined by analyses of aeromagnetic anomalies recorded 1,000 ft above the Biwabik in areas of known geology. The induced magnetization along the layers is relatively insignificant...

Measurements of erosion on miniature pediments in Badlands National Monument, South Dakota, show that during almost eight years, the pediments were lowered by sheetwash. The adjacent hillslopes have retreated leaving a belt of newly formed pediment from 6 to 12 cm wide at their bases. The hillslopes are rough and relatively permeable; the <span...