Publications

Seventeen representative samples of supergene sulphates from old workings on the Comstock Lode are described. They range from simple minerals such as gypsum and epsomite to complex aggregates of four or more distinct species. All are well known species except a mineral of the copper (chalcanthite) or magnesium sulphate pentahydrate group, with about half the magnesium replaced by copper, zinc, fer

The replacement ore bodies of the Metaline zinc-lead district, in northeastern Washington are limited to the greatly disturbed fault block through which the Pend Oreille River flows and are associated with the major faults but are not in them. They are mostly near the top of the Metaline limestone, of Middle Cambrian age, and below black Ordovician slate. The ores are generally in jasperoid and ar

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The igneous rocks and the minerals of Magnet Cove, Arkansas, have long interested geologists and mineralogists, but in much of the area rock‐exposures are so sparse that many of the geologic, relations have remained obscure. However, recent prospecting and the mining of titanium ores have uncovered rocks that throw new light on the geology of the region. The regional rocks of the area are sandston

The oldest igneous rocks in the Comstock District are amphibolites probably derived from basalts and of Triassic age. These are intruded by pre‐Tertiary quartz monzonlte and by granodiorite of Sierran facies, the latter not being exposed on the surface but found on mine‐dumps. Igneous activity recorded mainly in volcanic rocks was almost continuous throughout the Tertiary. Its products, in order o

Two of the numerous small dikes mapped on the areal geology sheet of the Franklin Furnace Folio (U.S. Geological Survey 161) as “Mostly basic, including nepheline tinguaite, leucite tinguaite, and camptonite” of post‐Ordovician age, have been found to be quite distinct from these alkalic rocks, and the two dikes in question are indistinguishable from the Triassic diabase found elsewhere in New Jer

Stratigraphy is concerned mainly with the genesis and interpretation of stratified rocks, which include some of wide extent and of great scientific as well as economic interest that are largely of chemical rather than of detrital origin. Chemical agencies have been recognized to some extent in genetic studies of these rocks, but little work has been done approaching in maturity the type of study n

As time marches on, historians are usually quite faithful in recording the activities of man, and it will usually be found that Mother Nature is even more meticulous in reflecting and preserving her experiences, more especially with regard to climate and vegetation. Just how much the activities of man have done to modify the natural conditions of a virgin country may in some respects always remain

The instrument herein described was originally designed and built to record the evaporation‐loss from a standard Weather Bureau pan for use in a study of the variation of flow in Santa Ana River. Valuable suggestions were made by various members of the Water Resources Branch of the Geological Survey in Southern California, and financial assistance for construction was given by F. C. Ebert and H. C