Southwestern California Research Articles

Nickeliferous laterites in southwestern California [discussion

Rejects a statement by P. E. Hotz claiming that nickel silicate-type deposits of New Caledonia were formed on unserpentinized peridotite, concluding instead that the deposits lie on ultramafic rock that is largely serpentinized.

Occurrence and Migration of Certain Birds in Southwestern California

Occurrence and Migration of Certain Birds in Southwestern California

Trichophyton Tonsurans in Minnesota

During the past few years there have been several publications concerning Trichophyton tonsurans, stressing the fact that the fungus is common in Mexico, Puerto Rico, and Southwestern United States, particularly Texas and California. There have also been reports of infections in areas away from the endemic ones. This communication will deal with the recognition of this fungus in Minnesota. Steves and Lynch (1947) reported the first case of T. crateriforme (T. tonsurans) in Minnesota. They identified the organism while investigating 747 cases of tinea capitis in the Minneapolis and St. Paul epidemic of 1945-1946. Cases of tinea capitis continue to occur sporadically in this region. Until recently T. tonsurans has rarely been considered as a possible etiologic agent. Because of the widespread dissemination of this organism, the dermatologist should be increasingly alert to the possibility of T. tonsurans as an etiologic agent in fungus infections. Howell et

Geologic history and correlation of the Jurassic of southwestern Oregon and California

The generally accepted correlations of the Jurassic of southwestern Oregon and California are as follows: Galice and Mariposa, Dothan and Franciscan, Myrtle and Shasta. The Dothan is said to be younger than the Galice. On the other hand it has been stated that the Dillard, the lower part of the original Myrtle, is the equivalent of the Franciscan. Since the Dillard unconformably overlies Dothan and Galice, it is clear that one or the other of these correlations must be erroneous. Evidence is presented to show that the Dothan is older than the Galice and cannot be the same age as the Franciscan. The Dillard, as originally defined, includes Knoxville (Upper Jurassic) and possibly infolded Lower Cretaceous, but the great bulk of the Dillard is to be correlated with the Franciscan. The Myrtle, as mapped and defined, includes beds of both Upper Jurassic and Lower Cretaceous age and at least one important unconformity. The name should be redefined and restricted or abandoned. The Nevadan orogeny took place in the late Kimmeridgian and uplifted the Sierra Nevada and depressed the belt now occupied by the Coast Ranges. In the geosyncline thus formed the Franciscan and Knoxville were deposited. There is no unconformity between the Franciscan and Knoxville; these groups were deposited during the Portlandian and Tithonian. At the base of the Lower Cretaceous is a widespread unconformity. The diastrophism which closed the Jurassic is called the Diablan orogeny.

San Andreas Rift in Southwestern California

That portion of California which lies southwest of the San Andreas Rift and south of the San Bernardino and San Gabriel ranges, generally known as the Los Angeles region, is described according to the evidences of physiographic and structural facts, so far as they are available. The structures are considered to be effects of shearing in massive rocks, especially controlled by bodies of intrusive granodiorite. The shearing is accompanied by intense compression, and stratified rocks are folded, but folding is not the primary structure. The analysis of the stresses results in the recognition of a rotational movement of the entire mass of the region, and the San Andreas Rift appears as a strike-slip fault between the batholith of Lower California and the pre-Cambrian element of southeastern California. The shearing is analyzed according to mechanical principles, and deductions are made as to the origin of the stress. The dominant stress is found to have been oriented from south toward north. Several hypotheses are presented to account for it and, while none is regarded as established, that which deduces the pressure from the dynamic energy of the batholiths through metamorphism of crystals appears to have the best chance of survival.

Willett's 'List of the Birds of Southwestern California' A Revised List of the Birds of Southwestern California George Willett

Willett's 'List of the Birds of Southwestern California' A Revised List of the Birds of Southwestern California George Willett

The Seismological Society of America

FOUR volumes of the Bulletin of this society were completed with the last year. They contain many papers of interest and value, most of which have been noticed in these columns, and several -evidently the work of novices-which the Publication Committee might with advantage have suppressed. The first part of the fifth volume, which has been issued recently, contains six papers, three of which are of general interest. Of the others, one on the seasonal periodicity of earthquakes is inconclusive. Mr. Carl H. Beal describes an earthquake which originated near the town of Los Alamos, in southwestern California, on January 11 last. This is probably the first earthquake in which the long-distance telephone has been used in the collection of records. Prof. J. C. Branner insists on the untrustworthiness of personal impressions on the direction of an earthquake-shock, and he urges that, in investigations of an earthquake, the question dealing with such impressions should be omitted. It has long been known that single observations on the apparent direction of the shock or on the fall of a column, etc., are valueless, the apparent direction being almost invariably perpendicular to the principal walls of the house in which it is observed. But the average of a large number of personal observations within a limited area has been found in several cases to coincide with the direction of the area from the epicentre. Moreover, after the Tokyo earthquake of June 20, 1894, Prof. Omori measured the direction of fall of 140 stone lanterns with circular bases in Tokyo, and the average of these measurements coincides exactly with the direction of the single great oscillation registered in that city.