Add to ORKGFully half of the many inquiries that reach the Arizona Bureau of Mines can be answered satisfactorily only by one with a rather thoro knowledge of the geology of Arizona. Unfortunately, practically nothing descriptive of the geological conditions existing in fully one-half of the State has ever been published, and even where some work has been done, the available published data bearing on the results secured are often decidedly meager, and are admittedly inaccurate in some cases. No fairly reliable reconnaissance map of Arizona has ever been prepared, and such a map cannot be completed without extensive field investigations. 40 p.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS)...