Texas Rocks and Minerals: An Amateur's Guide

Book Company, Inc., New York, N. Y. (second edition, 1951).

Rocks and Rock Minerals, by Louis V. Pirsson, revised by Adolph Knopf. John Wiley and Sons, Inc., New York, N. Y. (third edition, 1947).

A Field Guide to Rocks and Minerals, by Frederick H. Pough. Houghton Mifflin Company, Boston, Mass. (third edition, 1960).

Mineral Facts and Problems, by the Staff of the Burea...