Abstract: "Lead-alpha activity age determinations were made on zircon from seven granitic rocks of central and southeastern Alaska. The results of the age determinations indicate two periods of igneous intrusion, one about 95 million years ago, during the Cretaceous period, and another about 53 million years ago, during the early part of the Tertiary. The individual ages determined on zircon from 2 rocks from southeastern Alaska and 1 from east-central Alaska gave results of 90, 100, and 96 million years; those determined on 4 rocks from central Alaska gave results of 47, 56, 58, and 51 million years."

From abstract: To help the mining industry of Alaska and to assist in the development of the mineral resources of the Territory have been the prime motives of the Geological Survey's investigations in Alaska during the past 35 years, in which nearly one half of the Territory has been covered by its reconnaissance and exploratory surveys. It was natural, therefore, that the Alaska Railroad, when it undertook intensive consideration of the problem of finding tonnage that would increase its revenues, should look to the Geological Survey to supply technical information as to the known mineral deposits along its route and to indicate what might be done to stimulate a larger production of minerals and induce further mining developments and prospecting that would utilize its service.

"This study constitutes a determination of the extent to which it is feasible to use airborne, high-sensitivity gamma-ray spectrometer systems for uranium reconnaissance in the State of Alaska, and specification of a preliminary plan for surveying the entire state of the 1975-1979 time frame."--Page iii.

Report on ecological investigations sponsored by U.S. Atomic Energy Commission.

From letter of transmittal: It is believed that this report will stimulate the mining industry by making available, in compact form, the accumulated results of the experience of mining men in this field and by directing attention to those mining methods developed in older districts which appear to be adapted to the conditions prevailing in Alaska.

Introduction: This work is an alphabetical list of the geographic names that are now applied and have been applied to to places and features of the Alaska Landscape.