116 Feather stonJiaugh''s Geological Report, 



of blue and reddish clay, then thirty feet of clays very much 

 intermixed with gypsum, and lower down, to about two hun- 

 dred and twelve feet — the greatest depth they have been 

 obliged to go, for here the boring instruments drop into an 

 unmeasured deposite of brine — through masses of gypsum,* 

 sometimes containing a little clay, and occasionally compact 

 argillaceous laminae, with ferruginous pebbles and pieces of 

 sandstone. In the immediate vicinity of these salt-wells are 

 extensive dry deposites of gypsum, where it is quarried for the 

 use of the adjacent country. There are also others higher 

 up the valley, nearer the sources of the Holston. The aver- 

 age quantity of brine necessary to make a bushel of salt at 

 Kenawha is said to be about seventy gallons, but at Saltville, 

 twenty-four gallons are sufficient to make one bushel, and this 

 of the purest kind, there being no traces of muriate of lime 

 in it, which is so troublesome at the other salt-works where 

 the brine acts upon the calcareous rocks. The brine here 

 comes from the pumps loaded with sulphate of lime or gyp- 

 sum, which is deposited in the form of blocking in the pans 

 where the brine is boiled. These salines appear to be in- 

 exhaustible. Ligneous fuel, however, is rapidly disappear- 

 ing from the neighborhood, and the proprietors would do well 

 lo institute a search for coal, which may probably be found in 

 the vicinity. 



The geological position of Pittsburg is interesting. The 

 Alleghany and Monongahela rivers unite here to form the 

 Ohio. In ancient times, before the streams of this continent 



* There is a stnl;ing analogy belvveen this deposite and those of Ischil, on the 

 Gmunden lake, in German}-, which originally gave its name to Salzburgh. 

 There is an interesting paper in the American Journal, Sec. for January, 1836, 

 from an officer in the United States navy who visited those salt-works, in which 

 he says, "The gangue of the salt, if the word may be ustd, is composed 

 chiefly of a clayey earth, mixed up with irregular blocks of sulphate of lime. 

 The salt is mingled with these, usually in strata of from six inches to two feet 

 in thickness." Fresh water is let into the chambers of these deposites, and 

 when saturated is drawn off'. This is probably the natural manner in which 

 the brine Is formed at Saltville. 



