1760 



The Corneli, Reading-Courses 



aggregate area of about fifteen thousand square miles. Not all the areas 

 embrace an entire county, as smaller areas were sometimes made the 

 unit in earlier work. The reports on many of these surveys are out of 

 print, but they can usually be consulted in the Annual Reports on the 

 Field Operations of the Bureau of Soils of the United States Department 

 of Agriculture, usually to be fotmd in the larger libraries. Every public 



Fig. 4.^ Map showing the distribution of the important types of soil-forming rocks in 



the State 



1, Calcareous (lime-bearing) rocks. Includes limestone, dolomite, and calcareous shales 

 and sandstone 



2, Gray, blue, and a little brown shale and sandstone. Non-calcareous, horizontally 

 bedded 



3, Red shale and sandstone. Non-calcareous 



4, Gray and blue shale, slate, and sandstone. Much folded and somewhat metamor- 

 phosed 



5, Igneous rocks. Mostly siliceous 



6, Unconsolidated material of the Atlantic coastal plain 



library should have a complete set of these reports, the cuiTcnt vokunes 

 of which can be procured through the Congressman from the district. 



The making oj soil 



Rain, wind, frost, glacial ice, streams, waves, plants and animals, and 

 the solvent power of water, are at work continually on every exposed 

 rock. By these agencies mountains have been reduced to plains, and 

 lakes, and even oceans, have been filled to the condition of dry land. 



