Since the happy days of apprenticeship in Economic Geology on the U. S. Geological Survey when under the inspiring guidance of Waldemar Lindgren and Frederick L. Ransome he first acquired an interest in the application of geology to mining, the writer has been especially fascinated by the interpretation of ore textures under the microscope. Through twenty-five years of subsequent teaching of Economic Geology in the laboratory at The University of Chicago this interest has increased, as he has realized more and more fully how much the critical interpretation of the textures of ores as seen under the microscope contributes to a sound diagnosis of the origin of the ore deposits.
In the study and interpretation of microscopic ore textures, as in most relatively new fields, a certain period of seasoning must be passed through before sufficient agreement develops among the research workers to warrant the preparation of a text. In the present case the writer believes that season has been sufficient and that the needs of students warrant the presentation in a brief book of the more salient information on ore textures now mainly scattered through the technical journals and governmental reports. Widespread agreement does not yet exist with respect to the significance of all ore textures. The book is intended to be not a manual but a laboratory aid to graduate and advanced undergraduate students in their microscopic studies of ores, and the writer hopes it may also be of aid to research workers.
In this as in most . . .