THE POTOMAC AND RAPPAHANNOC. 285 



easterly direction. At the point at which the Potomac 

 again resumes its course eastward to the ocean, its distance from 

 the river Rappahannoc does not exceed six miles in a straight 

 line. High land separates these streams. — The navigation of 

 the Potomac is much superior to that of the Rappahannoc, 

 and very great advantages would accrue from their junction at 

 this point; but the task of connecting them by a tunnel through 

 this narrow ridge, must be reserved for wealth and population 

 infinitely superior to that of the present age. — From Piscataway 

 to Potomac creek, the course of the river Potomac is paral- 

 lel to that of the sea coast, and measuring along a line run- 

 ning about S. 60° east*, the distance from the present coast 

 will be about 120 miles. — The range of sand stone rock lies 

 on the west side of the Potomac, beginning a few miles be- 

 low the bend, and continues running in a direction parallel to 

 its south western course, until the river again turns to the east- 

 ward. — There it crosses under the ridge which separates the 

 Potomac from the Rappahannoc, reaches and crosses the 

 Rappahannoc, and appears to run out about two miles on the 

 west side of this river. — I have not seen, or heard of its hav- 

 ing been found further to the south west for 50 or 60 miles, 

 but it is again found 12 miles above the foot of the falls 

 of James's river, in a situation much higher above the tide, 

 than at the Potomac and Rappahannoc, a situation appa- 

 rently inexplicable upon any supposition which applies to the 

 sand rocks of these latter rivers; and yet, so exactly similar 

 are these James's river rocks, in all their geological character- 

 istics, that it is impossible not to attribute their formation to the 

 same process of nature. The present state of these rocks is 

 very irregular. — They make their appearance upon the slopes 

 of the vallies and water courses, along the whole line which I 

 have described, in large disrupted masses, or in regular ranges, 



* The courses of north 40° east, and south 60° east, form a spherical angle, at which, 

 with occasional, but never very great variation, the .two principal planes of Rhomboidal crys- 

 tallization, not only of our rocks of every description, granite, slate, marble, limestone, 

 wacke, and of all those numerous and ambiguous genera of rocks, lying in character, be- 

 tween a distinct granite on one side, and homogenous basaltes on the other, intersect each 

 other, but which decide the position. — I had almost ventured to say the crystallization of 

 the constituent parts of the globe, from the equator to the pole, and from the* Mississippi at 

 least to the Atlantic. On inspection of any map of North America, especially if drawn ore 

 Mercator's principle, this fact is evident to the eye. 



