220 Geology, ^c. of Tennessee, <^c. 



strata lie in a course northeast and southwest, the same a«f 

 the general course of the mountains. The angle which they 

 make with the horizon is very variable, from 25° to 46°. The 

 colour of the rock varies from blue, and pale blue, to gray, or 

 grayish white, frequently it presents a dull earthy appearance. 

 The fracture is more or less conchoidal. Sometimes the rock 

 assumes a different character, and the fracture is uneven, and 

 'tjie texture firm. This last is distinguished from the former, 

 not only by the fracture, but by the colour. It is usually spo- 

 ken of by the inhabitants as the gray limestone, the colour of 

 the other being usually of a bluish cast. It differs from that 

 also by being less brittle, and possessing the quality denomina- 

 ted by stonecutters, "tough.''^ Inconsequence of this, and 

 its enduring heat better, it is more frequently used in building 

 than the other. This variety of limestone is not uncommon. 

 Its colour is not always gray, sometimes it is a reddish brown, 

 and sometimes white. Immense quantities of it, possessing 

 either a grayish or reddish brown colour, are found in the vi- 

 cinity of Knoxville, East Tennessee. One range, of it is 

 crossed by every road, passing to the south and east of Knox- 

 ville. Its appearance is that of some variegated marbles ; 

 white veins penetrate it, and wind through it in every direc- 

 tion. Whether any part of it has a texture sufficiently fine 

 and firm to be wrought to advantage, is yet to be determined. 

 To the eye of a superficial observer, there are many indica- 

 tions that it has. A specimen of verj fine white marble, re- 

 sembling the Italian white, was shown me in Augusta county, 

 Virginia, which was found 1 5 miles from Staunton, where there 

 is said to be a considerable quantity of it. 



Limestone country in Horizontal Strata. 



The second great division of the limestone country extends, 

 on the route which I took, two hundred miles from the Cum- 

 berland mountain, and others associated with it southwest, as 

 far as the Dividing Ridge, which separates the waters flowing 

 into the Tennessee from those which proceed direct to the 

 gulf of Mexico. The grand circumstance which distinguishes 



