Publications

The two formations and eight members that constitute the Upper Cambrian in the Llano uplift of central Texas are described or redefined, and their lithic characters in 19 measured sections are graphically summarized. Standard reference to them is thus furnished.The Riley formation comprises the basal Paleozoic strata of the Llano uplift. Its initial sediments were deposited on a submerged pre-Camb

By definition European geologists consider a sequence of limestones, sandstones, and shales, the beds of which are thin, regular, and alternating, and which are deposited in a geosyncline or foredeep shortly before a major orogeny, as the flysch. The waste products that accumulate as a deposit flanking mountains and built in part of the deformed flysch make up the molasse. In field practice the gr

Complete chemical analyses, including the spectrographic determination of 44 trace elements, have been made of six representative specimens from each of the six map units constituting the Oliverian magma series in the Mt. Washington quadrangle of New Hampshire. Potash is systematically higher than soda. An increase in silica, which ranges from 56 to 75 per cent, is accompanied by the usual variati

This report is on result of a long program of geologic investigation in south-central Idaho, undertaken as an aid in the development of the mineral resources of the region. This quadrangle was examined because of the exceptional opportunities for the study of stratigraphy and structure afforded by the Lost River Range, which is the highest in Idaho and contains comparatively few intrusive igneous

Determination of the ground‐water supply available from any aquifer or in any specified area requires not merely the application of specific quantitative methods but also a broad and accurate knowledge of the geologic, hydrologlc, and geochemical factors that are involved, and consideration of the economic and legal limitations. Further research is needed as to geologic texture and structure in re

Scheelite accompanies ferberite as an ore of tungsten at many localities in the Boulder tungsten district. It is only of accessory importance in most veins, but in a few mines it affects grade of the ore substantially. It occurs in small veins, in vugs, disseminated in sericitized rock, and in gouge and minute fractures in shear zones. The vein and shear-zone deposits are the most important econom

A record of the activity of Parícutin Volcano, Michoacán, Mexico, is shown in the diagram of eruptive characteristics, Figure 1, covering the period December 31, 1946 to March 31, 1947, and is supplemented by the maps of the areal extent of the lava flows, Figures 2 and 3. This continues the previous record for the period from September 18 to November 30, 1946 [Trans. Amer. Geophys. Union, v. 28,

This paper gives a brief summary of studies of the value of the electrical log for estimating ground‐water supplies and the quality of the water in them made in Texas by the United States Geological Survey and cooperating parties.The electrical log has been found to be especially valuable in the Coastal Plain Region of Texas where the rocks consist mostly of a succession of clays or shales or sand

No abstract available.

In 1942-44, about 120 Connecticut pegmatites were examined for beryl and other minerals during investigations by the Federal Geological Survey. Most of the pegmatites lie in the Middletown district, occurring principally in the Bolton schist and Monson gneiss. The pegmatites range from distinctly zoned bodies to those that are essentially uniform mixtures of the component minerals. Beryl in the zo

The zinc content of thirty different kinds of plants growing on slime ponds containing on the average 12.5 per cent zinc were determined by the dithizone method. The zinc content ranged from 39 p.p.m. in the fruit of the false solomon's seal (Smilacina racemosa) to 5,400 in the horsetail (Equiseteum arvense}. This latter plant varied considerably in zinc at different places on the slime ponds. The

The Upper Mississippi River Embayment is a region of about 45,000 square miles in the Mississippi River Valley extending from the vicinity of the 34th parallel northward to the mouth of the Ohio River. It includes parts of Arkansas, Mississippi, Tennessee, Kentucky, and Missouri. In 1940 about 2,700,000 people inhabited the region.Ground water is one of the most valuable natural resources of the r