The Hood Spring quadrangle, in the central part of Brewster County, Texas, contains a segment of the southeast rim of the Marathon basin.

Preparation of a desk-side reference manual of Cretaceous foraminifera was undertaken as a project of the Bureau of Economic Geology, where I was a staff member during the summers of 1945 to 1947 and during July of 1951.

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.

Sixty-eight species of trilobites, 10 species of inarticulate brachiopods, two species of articulate brachiopods, one ostracode and fragments of sponges, pelmatozoan echinoderms and unidentifiable organisms constitute the faunas of the Riley formation.