The Oatman and Katherine districts have produced more than thirty million dollars worth of gold and silver yet no complete report on the geology and ore occurrence of this interesting region is available though numerous short papers on various phases of its geology or the mining operations conducted there have been published from time to time. A thorough study of the Oatman District was made by Dr. F. L. Ransome and a preliminary report based on that study was issued by the United States Geological Survey in 1923. The detailed descriptions of the rocks and the excellent map of the district accompanying this report have been of great value to the operators in this district. As Dr. Ransome has left the Geological Survey, it is hardly likely that a complete report will be written by him and published. Among the earlier accounts of the district, that by Mr. F. C. Schrader is, by far, the most complete. Although Schrader's report is based upon a reconnaissance examination of the district, as stated in the introduction, it served a useful purpose until superseded by Ransome's more detailed studies. Schrader's work, which preceded Ransome's by fifteen years, was done at a time when a large number of the properties were operating. The bulletin, therefore, contains much information on the character of the vein fillings and the grade: of· the' ore mined. Both Ransome's and Schrader's bulletins have been drawn on freely for information on,the underground workings of properties now inaccessible. Frequent short notices in the technical press deal chiefly with mining or metallurgical problems, and rarely make more than a brief mention of the geology, and then usually treat of the geology of some particular mine rather than of the district,as a whole.