CHAPTER LXXIII, 



EEPORT OF THE GEOLOGY OF MADISON COtTNTY, 



BY EDWARD ORTON,, ASSISTAJST ©B0I.OGI8T 



Madison cotinty is bonnded on the north hy Union, on the east by 

 Franklin and Pickaway, »n the south by Fayette, and on the west by 

 Greene, Clarke, and Champaign counties. 



Its surface is comparatively level. Its lowest land is found in the 

 aoutb-eastern corner^ near Mount Sterling, in the valley of Deer Creek, 

 Its highest land lies to the west and north-west of London, and is about 

 1,100 feet above the level of the sea. The range of the county does not 

 probably exceed 300 feet. The altitudes of a few of the principal points 

 in the county are subjoined ; 



London, 1,010 feet above- tide- water. 



West Jefferson, 830 feet above tide- water'. 



Mount Sterliag, 866 " " 



Midway, 950 " " 



South Solon, " " 



County Iniirmary 1,100 feet abo-"e tide-water. 



County line on Xenia pike, west of Loudon, 1, 100 feet above tfde- water.- 



OMinger'a Hill, west of Summerford, 1,100 " " 



Of tliese altitudes, all but the tirst were obtained by the ba>ometer, and 

 must be taken as approximations only. They sufi&ce to show, however, 

 the very great degree of uniformity that prevails in the surface of the 

 county. A very large part of its area lies at altitudes varying betweert 

 950 feet and 1,050 feet above the sea. Notbwithstanding this uniformity 

 of level, there ia but very little swamp-land in Madison county. The 

 slopes, though very gradual, are so distributed that the water always^ 

 knows which- way to go. Between those sources of Little Darby Creek 

 that lies within the county, and the point where the creek crosses the 

 county-line, there is a fall of scarcely less than 200 feet. The distance \% 

 about 15 miles and the average descent is between 13 feet and 14 feet to 

 the mile. 



Deer Creek descends, from its head-springs near Summerford, 300 feet, 

 in its diagonal course of 20 miles across the county — an average fall of 

 15 feet to the mile. 



