Publications

The Committee was enlarged during the past year by one more member, Prof. J. E. Church of Reno, Nevada, Chairman of the Committee on Snow, who agreed to serve on it while the Chairman of the Committee on Glaciers in turn accepted membership on the Committee on Snow. Thus the two Committees, whose spheres of work are in some respects intimately related, have been brought into closer touch with each

Two meanings are unfortunately given to the term geophysics. In the broad sense, based on the etymology of the term, geophysics means the physics of the Earth. This is its significance in the names “Geophysical Laboratory of the Carnegie Institution of Washington,” “International Union of Geodesy and Geophysics,” and “American Geophysical Union.” In this sense the sciences of geology and hydrology

The withdrawal of water from a well necessarily produces a drop in water‐level in the well. The ground‐water level in the vicinity of the well from which the water is withdrawn likewise declines, but the amount of decline decreases with increasing distance from the well, so that a cone of depression of the water‐surface in the vicinity of the well is produced. The cone of depression is an actual w

The membership of this Committee is as follows: C. S. Howard, Chairman, U. S. Geological Survey, Washington, D.C.D. G. Thompson, U. S. Geological Survey, Washington, D.C.A. C. Lane, 22 Arlington Street, Cambridge, MassachusettsC. S. Scofield, Bureau of Plant Industry, U. S. Dept. Agri., Washington, D. C.I. A. Denison, U.S. Bureau of Standards, Washington, D.C.T. G. Thompson, University of Washingt

In accordance with the by‐laws of the Section, the Committee on Underground Waters has been reconstituted during the past year. With their research interests turning to other subjects, several members have dropped out, and four new men have been appointed. In order to maintain contact with the work of related committees, Charles H. Lee, Chairman of the Committee on Absorption and Transpiration, an

Since the last meeting of the Section of Hydrology there has been a change in the organization and membership of some of the research‐committees, one relating to rainfall, of which Merrill Bernard is Chairman, and one relating to runoff, were created to replace the one committee which had functioned heretofore on both rainfall and runoff. This action by the officers provides for greater participat

The work described in this paper was all done in connection with dam‐site investigations and was not directly connected with hydrology. However, geophysics is coming to have a place in hydrologic investigations, and these results may throw some light on what can be accomplished by resistivity‐measurements.We have found that,for many questions not involving exact determinations of depth, resistivit

The modern deep well makes it possible to determine the temperatures of the rocks to depths exceeding two miles, and the rock‐samples obtained at these great depths enable the geologist to estimate the depths to the deeply buried basement‐rocks to a rather high degree of precision. The latter estimates are now being supplemented to a certain extent by the precision‐measurements of geophysicist, so

Recent studies have shown that relatively impermeable clay beds are widespread on Long Island but that erosion channels cutting through them permit restricted recharge of the underlying beds in some parts of the island. Of the more than 200,000,000 gallons of water a day now pumped from wells, about 65 per cent. comes from the surficial beds of Illinoian or Wisconsin age. Because of the restricted

In the past five years members of the Geological Survey have gained experience in making isometric block diagrams of mines and mining districts as well as of surface features. This paper presents nothing new, but aims to assemble scattered information on a much neglected method of geological illustration. Plotting mine workings on isometric paper is the usual method but is extremely time-consuming

Some of the recent floods in the United States have indicated that, in any appraisal of the potentialities of a river system for producing floods, more significance than has perhaps been customary should be attached to the magnitude of the great floods of the past, as disclosed by Nature's records of them. A conspicuous part of the work of rivers in the processes of dynamic geology is associated w

The La Plata Mountains, in southwestern Colorado, have long been known as an example of a mountain group of the laccolithic type, although it has been recognized that the igneous geology was much more complex than that of typical laccoliths. A restudy of the ore‐deposits of the District, now in progress, has thrown new light on the mode of intrusion of the igneous rocks (E. B. Eckel, Resurvey of t