216 Geology, S/c, of Tenntsset, ^c. 



structed. It is composed of fine silicious grains, is easily 

 wrought, and from its colour, has the appearance at a small 

 distance of white marble. 



Beautiful Breccia. 



It is also in the yalley of this river, and not flir from its fa- 

 mous passage through the Blue Ridge, that immense quarries 

 of beautiful Breccia have been opened. This rock was first 

 brought into use by Mr. Latrobe, for some years employed by 

 the government as principal architect. It is composed of peb- 

 bles, and fragments of siUcious and calcareous stones of almost 

 every size, from a grain, to several inches in diameter, strongly 

 and perfectly cemented. Some are angular, others rounded. 

 Their colours are very various, and often bright. Red, white, 

 brown, gray, and green, are alternately conspicuous, with 

 every intermediate shade. Owing to the silicious stones which 

 are frequently imbedded through the mass, it is wrought with 

 much difficulty ; but when finished, shows a fine polish, and is 

 unquestionably one of the most beautifully variegated marbles, 

 that ever oxiiamented any place. It would be difficult to con- 

 ceive of any thing more grand than the hall of the Representa- 

 tives, in the Capitol, supported as it is by twenty or thirty pil- 

 lars formed of the solid rock, and placed in an amphitheatrical 

 range ; each pillar about three feet in diameter, and twenty in 

 height. Some idea of the labour which is employed in work- 

 ing the marble may be formed from the fact, that the expense 

 of each pillar is estimated at five thousand dollars. The spe- 

 cimens in your possession, are good examples of its general 

 structure, but convey no adequate idea of its beauty. 



Petrifaction of Wood, 



It will be proper to notice in this place, a petrifaction of 

 wood which is found on the road from Washington to Freder- 

 icksburgh, 16 miles from the latter, and four miles north of the 

 court-house in Stafibrd county. It is remarkable for its size, 

 rather than for any singularity in the composition. It wa» 



