21

and many new problems discussed and solved; but only such scientific investigations should be undertaken by a State survey as have a direct bearing upon the main point at issue. All others should be left to the specialist. Therefore the principle upon which I have endeavored to base this survey, and to impress upon each of my co-laborers, is, that while the work of the survey is economic geology, the only way to obtain accuracy of results is by application of the highest scientific methods.

In order that such work may be prosecuted in a manner to be of real benefit to the people of the State and at the same time with the requisite degree of rapidity, it is essential that two things be fully determined; first, the topography of the country must be known and mapped; and second, the general stratigraphic geology must be sufficiently well known to permit the geologist to devote himself to the economic features of his work. Neither of these essential helps exist here.

Accurate maps are of the greatest importance. They must show not only the correct geography of the country (although this is a great help), but must also include its varied topography. "Accurate topographic maps are essential to geologic study. Upon such maps the field geologist records his observations relating to the character of the rocky strata, the strikes, dips, etc., just as the land surveyor records his courses and distances upon a plat; and when the observations are completed he is able to take in the whole series of records at a glance, to generalize and to classify them, and to perceive the relations of the different veins and beds which it is desirable to distinguish, and thus in many cases to determine the relations of the strata far beyond the reach of actual observation, and sometimes to estimate the extent, thickness, and depth of the coal seams and other mineral deposits hundreds of feet below the surface. The topographic map is as essential to the field geologist as the plat to the surveyor, the plan and profile to the engineer, or the diagram to the architect."

At present there is no map of the State on which even the geography is shown correctly enough for our uses, and there is no State map at all giving any idea of the topography.

In our work, therefore, we have been obliged for the most part to use the county maps furnished by the Land Office, which, being compiled from the work of different surveyors, often show considerable discrepancies