74 Geology of the Kiskiminitas. 



cords of the revolutions of nature, I had anticipated the discovery 

 of many interesting and valuable facts, that would have been useful 

 in elucidating the geology of the valley : opportunities for examining 

 the interior strata of our mountains, or of the rocks generally, in this 

 country are so rare, that it will probably be a long time before so fa- 

 vorable a chance again occurs. The roof of the tunnel is tw6 hun- 

 dred feet below the top of the mountain, or spur, as it is called. 

 The time occupied in performing this work was eighteen months ; 

 and eleven thousand pounds of gunpowder were expended in blast- 

 ing the rocks. 



Geology of the Kiskiminitas. 



The rock strata of this region, like that of the Monongahela, con- 

 sist of alternate beds of sandstone, limestone, slaty marl of different 

 colors, and coal and shale, extending to the depth of many hundred 

 feet. At the salines, twelve hundred feet of these deposits have 

 been explored, seven hundred below the bed of the river, and five 

 hundred above. The upper surface stratum of soil, where it is in a 

 situation to admit of cultivation, produces good crops. The only 

 ores found are those of iron, which is of the argillaceous species, and 

 it is generally found in slaty marl or clay. The deposits of iron in 

 the Laurel and Chesnut ridges, are usually at a greater elevation 

 than the coal ; in one place, at the foot of the ridge, a thick bed of 

 coal reposes immediately on the iron ore deposit. 



The salt wells at Kiskiminitas and Connemaugh, are singular in 

 one respect; they afford no petroleum, but an abundant supply of 

 carburetted hydrogen. When a well is first opened, the gas rushes up 

 with such violence as to force the water, in a column or jet, thirty 

 feet above the mouth of the well, returning at intervals,, and contin- 

 uing an hour or more at each period. The absence of petroleum 

 seems to indicate some peculiar state of the coal beds in consequence 

 of which they afford the gaseous and not the fluid products of ve- 

 getable decomposition, the difference consisting chiefly in the differ- 

 ent proportions of the carbon and the hydrogen. 



The following section of the rock strata at the salt works on the 

 Kiskiminitas, five miles below Saltsburgh, will give a correct view of 

 the geological structure. It was furnished by A. Boggs, Esq., who 

 resided several years at this place and superintended the boring of 

 several salt wells, and to whom I am indebted for much valuable in- 

 formation. 



