THE science of topography deals with the various natural and physical features of the earth's surface. These features are determined by the manifold constructive and destructive processes of nature, and their many diverse forms and characteristics are dependent primarily upon geologic structure. Thus it is that a close relationship exists between the rocks of a region and the topographic features of the country wherein they occur. Again, the existence of all sorts of mineral wealth is dependent upon the nature of the rocks, and their extension is directly connected with the topographic features represented upon the enclosing land area. In studying any district with a view to deciphering its geological structure, to locating any mineral deposits it may contain, and to ascertaining, so far as a surface examination may show, their probable and economic possibilities, it is therefore of primary importance to have at hand a correct topographical map of the area under investigation.