THE UNITED STATES GEOLOGICAL SURVEY. 495 



eral survey. If agreeable to the States, co-operation will be con- 

 tinued on essentially the same conditions in the future as in the 

 past. 



Relations to Agriculture. The work of the Geological 

 Survey touches the interests of the agriculturist by furnishing 

 data in relation to the distribution and supply of mineral ma- 

 nures, marls, phosphates, etc., and the distribution of soils. The 

 soils are the direct result of the decay of rocks, and in the non- 

 glaciated areas of the United States the geological maps, showing 

 the distribution of the rocks, are practically soil maps, as the 

 clay, lime, sand, and other constituents of the rocks are the chief 

 ingredients of the soils. The maps of the superficial deposits 

 within the glaciated region will show the distribution of the 

 different types of soils produced during the drift period, and 

 those of the deposits without the glaciated region, the drift ma- 

 terials deposited in the river valleys. 



In the arid and semi- arid region all questions of the occur- 

 rence and distribution of artesian water and water supply for 

 irrigation are of great importance to the farmer, and a knowledge 

 of the underlying geology will be of service in determining ex- 

 tended systems of drainage in areas provided with abundant 

 water supply by precipitation. The study of the materials enter- 

 ing into the construction of highways is also of moment to the 

 farmer, as good roads mean so much to his industrial and social 

 development. 



It is not practicable adequately to summarize in a few para- 

 graphs the results of the work of the survey for the period 1879- 

 1894. A somewhat full statement has been made in the fourteenth 

 and fifteenth annual reports of the director of the survey. But, 

 in brief, it may be said that there are completed of topographic 

 surveys, six hundred and eight thousand six hundred and fifty 

 square miles, of which five hundred thousand are available for 

 areal geologic mapping ; of geologic mapping, one hundred thou- 

 sand square miles, of which sixty thousand are ready for the 

 engraver; of special geologic and miscellaneous investigations, 

 fifteen large annual reports, one hundred and sixteen bulletins, 

 and twenty-four monographs. Many thousand topographic and 

 special geologic maps have been printed and distributed, and, 

 what is most important, a material and intellectual equipment 

 has been assembled that will have a marked influence in all 

 future work. 



Under the statutes the function of the Geological Survey is to 

 make a topographic and geologic map of the United States, and 

 to continue the examination of its geologic structure and mineral 



