Base maps that involve the compilation of new data should be prepared by either the topographic branch or the division of Alaskan mineral resources. If a base map already published is to be reused it should be submitted to the chief topographic engineer or to the chief of the division of Alaskan mineral resources for approval. This procedure will insure a single standard of geographic accuracy in maps appearing in Survey publications. A geologist who requires a base map that includes new topographic data should address a request for its preparation to the chief geologist, who, through the Director, will refer the request to the topographic branch. The request must be accompanied by a full statement regarding the proposed report and the time when it is likely to be submitted. The preparation of such base maps by draftsmen in the division of geology, the land-classification board, the water-resources branch, or the section of illustrations has been discontinued except for the minor adaptations provided for above. If a report requires the preparation of a base map that includes no new topographic data such a map must be compiled from other authentic maps by the division or branch in which the report originates. If, however, no draftsmen are available in that division or branch, an arrangement can be made with any other branch--as the topographic or publication branch--that may have draftsmen available, with the understanding that the cost of the work shall be reimbursed to the branch doing the work by the branch ordering it. For indicating geologic and other data, however, an author may make use of an authentic base map already published, and after it is reduced or enlarged to appropriate scale by photography such a map may suffice for transmittal with a manuscript. MATERIAL AVAILABLE FOR BASE MAPS. The maps already published by the Geological Survey[2] and other Government bureaus should always be consulted when a new base is to be compiled. The following list includes most of the maps available: 1. The Survey's regular topographic atlas sheets, published on three scales--15-minute sheets, scale, 1:62,500; 30-minute sheets, scale, 1:125,000; 60-minute sheets, scale, 1:250,000--approximately 1 mile, 2 miles, and 4 miles to 1 inch, respectively--and its "special" maps,[2] some of which are published on other scales. All these maps can be used as bases for detailed geologic maps, for compiling maps on smaller scales, and for revising other maps. 2. The United States part of the international map of the world, now being published on the scale of 1:1,000,000 (approximately 16 miles to 1 inch). Each sheet of this map represents an area measuring 6° of longitude and 4° of latitude. The published sheets of this map may be used as bases for general maps. The sheets are drawn on the scale of 1:500,000, and photolithographs on this scale are available for use as bases for geologic or other maps.