28(5 ON THE FREESTONE QUARRIES OF 



the external parts of which are generally weather-worn, flaky 

 and broken. The most extensive ranges are found in elevated 

 situations. — In the bottoms of vallies the masses that are found 

 there, appear to have fallen or slided down into the water course, 

 and the large masses that form the shore of Potomac and 

 Rappahannoc, are evidently much below their original posi- 

 tion. — On quarrying into the rock, the stone is found to be 

 amorphous, often stratified with layers of clay or pebbles be- 

 tween the strata, having also frequently upright joints or frac- 

 tures, so regular as to look like planes of crystallization. The 

 stone is however undoubtedly amorphous and aggregate. The 

 sand stone is covered with a superstratum of alluvial materials, 

 deposited to appearance, subsequent to the formation of the 

 stone; as sand, clay, gravel and pebbles, large and small, round- 

 ed by attrition out of many species of mountain stone. Along 

 this superstratum is found the ancient pebble beach, mention- 

 ed above, it forms the soil of the high land of the country, is 

 from ten to thirty feet deep, and where it is thinner along the 

 edges and slopes of the vallies, it seems to have been washed 

 away; for in considering the whole country, below the falls 

 of our rivers, we must necessarily perceive, that, if the phrase 

 may be admitted, it has no hills, but only vallies; that is, it 

 was originally a plain, into which the vallies have been gullied 

 by the drainage of water, on the receding and depression of 

 tbe ocean from its former level of 120 feet above its present 

 elevation. As I am not going to form any hypothesis, the dif- 

 ficulty arising from the existence of the ancient pebble beach. 

 at an elevation considerably above the still more ancient sand 

 beach, presents to me no difficulty in my opinion of the ori- 

 gin of this sand stone. 



The component parts of the stone are, 



Sand, generally sharp, but often rounded by attrition, of 

 variously sized grains, from very coarse to extremely fine. — 

 This forms the mass and body of the stone: — in this sand is 

 found a variety of extraneous matters. 



Clay, in nodules, generally round, sometimes, but rarely, 

 stratified as if deposited. The clay is white and remarkably 

 pure. The clay holes are very troublesome to the stone cutter 



