civ GENERAL SUMMARY OF SCIENTIFIC AND 



tutcs one of the principal lead-bearing rocks in the region. 

 The coal in the northeast part of the state is remarkable for 

 occurring in deposits of very limited area, but of great thick- 

 ness, sometimes as much as twenty-live feet, with very little 

 of the usually accompanying strata. These accumulations 

 are supposed to have been formed in small hollows in the 

 surface of the lower Carboniferous limestone. An artesian 

 well lately sunk in St. Louis, Mo., has a depth of 3843 feet. 

 Beneath forty feet of surface deposits lie the Carboniferous 

 rocks, the base of which was reached at 883 feet. These are 

 directly followed by the limestones and shales of the Trenton 

 or Cincinnati group, measuring 421 feet, beneath which were 

 not less than 2489 feet of magnesian limestones with sand- 

 stones and some magnesian slates the whole resting on red 

 granitic rock, which was penetrated forty feet. Salt water 

 was first met with in the Trenton limestone at 1220 feet, 

 and the lower strata yielded brines which contained seven 

 and eight per cent, of saline matter. The temperature in 

 these lower depths is from 105 to 107 Fahr. 



The paleozoic coal-formation of the Appalachian is for con- 

 venience divided into a lower and an upper series; the base 

 of the latter being the great Pittsburgh seam, which is a sheet 

 of coal known over a length of 225 miles and a breadth of 100. 

 Many questions have arisen as to the equivalency of the 

 seams in the lower coal-measures in different parts of the 

 coal-field. Counting from the base of the formation, which in 

 Ohio and Western Pennsylvania is found at a vertical dis- 

 tance of from 500 to 900 feet beneath the Pittsburgh seam, 

 Andrews and Fontaine, from their discoveries in AVest Vir- 

 ginia, have arrived at the very important conclusion that 

 the base of the coal-measures of the lower series on the Ka- 

 nawha is not less than 3100 feet below the Pittsburgh seam. 

 From this it would follow that in this region there was, at 

 the beginning of the coal period, a vast basin or depression 

 between highlands of older rocks to the southeast and the 



CD 



great plateau of the Waverley sandstones rising toward the 

 ridge of the Cincinnati uplift to the northwest. Nor was it 

 until this great valley had been filled up with 2000 feet or 

 more of coal-measures, including the important coal-beds of 

 West Virginia, that the general subsidence allowed the coal- 

 formation to be spread over the northwest plateau to a depth 



