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ground. Even the railroads do not appear in some of them. Therefore in endeavoring to carry on this detailed work we are met on every side by this great want, and much of the time that should be spent in the study of the geology must be given to correcting inaccuracies of the maps.

I have made an earnest effort to remedy this deficiency as far as possible. With this in view I went to Washington and had a conference with Major Powell, Director of the United States Geological Survey. As was stated in the First Annual Report, the topographic work carried on under the direction of the United States Geological Survey had been completed over some twenty-four thousand square miles in the center of the State. More exactly, the area covered by this work to June 1, 1890, was bounded by parallels 30°; and 33°;, and meridians 97°; and 99°; 30'.

These maps are engraved in sheets on the scale of two miles to the inch. On this scale each square degree forms four sheets. The principal points are located by triangulation, and the relative heights and differences of elevation are based upon the railroad levels of the country. Where there is a system of railroad lines which cross one another at various points a series of checks is afforded, and the degree of accuracy with which these levels are run is sufficient for the best of these maps. With these levels for a basis the reliefs of the whole country are determined by running lines of levels, plane table work, and barometric observation.

The maps are printed in three colors; the water-courses, lakes, etc., being in blue; the contour lines, by which each difference of elevation of fifty feet is shown, in brown; and the roads, railways, and other cultural features and lettering in black. They are by far the most accurate maps in existence of the region which they cover, and have been of great service, since they are fully sufficient for any but the most detailed work or that requiring a larger scale and greatest accuracy in detail. The intention was to extend eastward by this season's field work. I therefore requested of Maj. Powell that the field work of the present year be planned to meet our requirements more nearly, and instead of working to the east of the area given above that they take up that area lying between meridians 99°; 30' and 100°;. The completion of this tier of sheets would give us the topography of all the Central Mineral Region, part of the Abilene-Wichita country, a large portion of the Cretaceous area, and all of the Central Coal Field except that