REPORT OF THE STATE GEOLOGIST. XXI 



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 de- 

 termined ; first, the topography of the country must be known and 

 mapped ; and second, the general stratigraphic geology must be suffi- 

 ciently well known to permit the geologist to devote himself to the 

 economic features of his work. Neither of these essential helps exist here. 



TOPOGRAPHY. 



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 topo- 

 graphic 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 essen- 

 tial to the field geologist as the plat to the surveyor, the plan and pro- 

 file to the engineer, or the diagram to the architect." 



At present there is no map of the State on which even the geog- 

 raphy 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 com- 

 piled from the work of different surveyors, often show considerable dis- 



