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There appears to be surprisingly little definite information on the viscosity of lavas. With few exceptions writers content themselves with such general and indefinite terms as “mobile”, “viscous”, or “highly viscous”. Apparently the only attempts to actually calculate viscosity have been made on Hawaiian lavas.  ...

The feldspathic rock with which the titanium deposits of Virginia are associated appears to be an anorthosite, although the plagioclase is somewhat more sodic than in normal anorthosites. That is, this rock shows evidence of having been introduced as a mush‐like mass of crystals and intersititial magma, and of undergoing...

In recent years the Water Resources Branch of the United States Geological Surrey has given considerable attention to the relation of ground‐water to stream‐flow. One locality in which this relation is being studied is about 13 miles from Washington, near Colesvllle, Maryland, where a Kinnison float‐gage is being maintained in a well In connection with the operation of a...

A survey of the ground‐water resources of the region in which Houston and Galveston are situated was started in December 1930 by the United States Geological Survey in cooperation with the Texas Board of Water Engineers. In connection with this survey a special study is being made of the geochemical relations of the ground‐waters of an area about 25 miles wide and 90 miles long, extending from Galveston northwestward through Houston. This study considers the influence...

Students of Igneous phenomena have long since become familiar with the occurrence of rare minerals in pegmatitic bodies. The great local concentration of rare elements in pegmatite minerals provides a remarkably good opportunity for the Investigation of deep-seated rock constituents, for it is reasonable to suppose that these same elements...

The by‐laws adopted at the meeting of the Section of Hydrology in 1933 provided that the membership of research committees should be reconstituted every three years. There have, accordingly, been some changes in the membership of the Committee on Underground‐Water. Certain members have retired because of pressure of other duties or because they are no...

The water in artesian aquifers is confined under pressure. Under ideal conditions in a perfectly rigid artesian reservoir a change of pressure in one part of the reservoir should produce a corresponding change of pressure in all other parts of the reservoir. Theoretically, the transmission of pressure should take place rapidly and without any movement of water other than the small amount resulting from the compressibility of water. However,...

Snow‐fields and the so‐called névés of glaciers on lofty mountains often present a peculiar, honeycombed appearance, the surface being pitted with deep cell‐like hollows a foot or two feet in diameter and from a few inches to several feet in depth. When typically developed these hollows are closely spaced, the divides...

In the paper entitled “The measurement of the permeability of porous media for homogeneous fluids” by R. D. Wyckoff and others [42] a unit of permeability is proposed which is based on centimeters, seconds, and atmospheres of pressure (76 centimeters of mercury).In 1923, when the Hydrologic Laboratory of the United...

The personnel of this Committee during the past year, practically the same as during the previous year, has been as follows: C. S. Howard, Chairman—United States Geological Survey, Washington, D.C. L. C. Case—Gypsy Oil Company, Tulsa, Oklahoma. W. D. Collins—United States Geological Survey, Washington, D.C. H. F. Flynn—United States Engineer Office, 35...

In the following list brief statements have been added to certain references to call attention to special phases of ground‐water problems which are not apparent from the titles. Abstracts of most of these papers have been or will be published in the Annotated Bibliography of Economic Geology. ...

An outstanding achievement of the Section of Hydrology has been the work of the Committee on Glaciers in assembling the existing records of the advance and retreat of the glaciers in the Western States and in Alaska, encouraging various agencies in making periodic observations, systematizing and standardizing the work, and...

Active work under the recently authorized project relating to floods and their frequencies began in March, and such progress as may be reported at this time is largely that of organization and preliminary planning.One of the outstanding and impressive features of the organization is the provision for cooperative effort, whereby...

The ore deposits in the heart of the Leadville district, Colorado, are divisible, as shown by Emmons, Irving, and Loughlin,2 into two main classes on the basis of mineral composition: "contact-metamorphic" silicates accompanied by iron oxides, which adjoin an obscure igneous stock, and mixed sulphides accompanied by manganosiderite and quartz gangue, which cut the "contact-metamorphic" deposits and form a...

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In the foregoing outline of the structural history of the Grass Valley intrusive the vein fractures are regarded as elements of the internal tectonics of the intrusive body itself. They originated in an early stage of the structural development of the region, and are equivalent to the marginal thrusts observed in the Yose-mite and along the Mother Lode system....

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The Volcano Letter was an informal publication issued at irregular intervals by the Hawaiian Volcano Observatory (HVO) during the years 1925 to 1955. Individual issues contain information on volcanic activity, volcano research, and volcano monitoring in Hawaii. Information on volcanic activity at other locations is also occasionally included.The Volcano Letter...

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