These circulars issued from the Bureau of Economic Geology contain the record of cores and cuttings from well received and described in the Bureau.

Discovery of volcanic glass detritus in fluvial deposits of the middle Frio Formation (Seeligson and Stratton fields) of South Texas has resulted in a new classification of reservoir types (type I and type II) within this formation.

A deposit of phosphorite, estimated to be 11 feet thick, was found March 26, 1952, while the writer was mapping ancient sink fillings and collapse structures within the outcrop area of the Honeycut formation south of Marble Falls, Texas.

The suitability of salt domes in the east Texas basin (Tyler basin), Texas, for long-term isolation of nuclear wastes is being evaluated. The major issues concern hydrogeologic and tectonic stability of the domes and potential natural resources in the basin.

Uranium minerals have been found at several localities in west Texas. In the King Mountain area in southwestern Upton County carnotite forms coatings along joint planes and in borings in marineCretaceous limestone.

Proterozoic exposures in the Llano Uplift of Central Texas and in the Van Horn area and other smaller areas of western Texas represent less than one percent of the area underlain by Precambrian basement.

The Quitman Mountains are part of a narrow mountain range that extends southeastward from near Sierra Blanca, Texas (85 miles southeast of El Paso, Texas), into northern Mexico.

This report details the occurrence, geometries, scarp morphology, and paleorupture histories of Quaternary faults of northwest Trans-Pecos Texas and northern Chihuahua, Mexico.

The Hueco Basin of Trans-Pecos Texas, which formed in response to Cenozoic extensional tectonism, lies within the southern Rio Grande rift near the poorly defined boundary between the rift and the southern Basin and Range province.

The hydrochemical history of ground water in the arid southeastern Hueco Bolson and southwestern Diablo Plateau was investigated by collecting soil-moisture samples from unsaturated siliciclastic bolson-fill sediments and groundwater samples from the Diablo Plateau aquifer, the Hueco Bolson silt

Species of the genus Schwagerina occur in most of the outcropping limestones formed in the open, connected, epicontinental seas existing at the time of the initiation of the Permian fauna and flora.