RIVERS. 



291 



Natural Bridge, Virginia. 



the river has completely triumphed over the barrier of homogeneous hard blue rock that 

 intruded into its channel, and cut a passage through it from fifty to a hundred feet 

 broad, and from forty to fifty feet deep. The formation of the magnificent rock -bridge 

 which overhangs the course of the Cedar creek, one of the natural wonders of Virginia, 



is very probably due in part to the sol- 

 'I vent and abrading power of the stream. 

 This sublime curiosity is 213 feet above 

 the river, 60 feet wide, 90 long, and the 

 thickness of the mass at the summit of 

 the arch is about 40 feet. The bridge 

 has a coating of earth, which gives 

 growth to several large trees. To look 

 down from its edge into the chasm in- 

 spires a feeling answering to the words 

 of Shakspeare : 



" Come on, sir ; here's the place : stand still. 



How fearful 

 And dizzy 'tis, to cast one's eyes so low ! " 



Few have resolution enough to walk to 

 the parapet, in order to peep over it. 

 But if the view from the top is painful 

 and intolerable, that from below is 

 pleasing in an equal degree. The beauty, 

 elevation, and lightness of the arch, springing as it were up to heaven, present a striking 

 instance* of the graceful in combination with the sublime. This great arch of rock gives 

 the name of Rockbridge to the county in which it is situated, and affords a public and com- 

 modious passage over a valley which cannot be crossed elsewhere for a considerable 

 distance. Under the arch, thirty feet from the water, the lower part of the letters Gr. W. 

 may be seen, carved in the rock. They are the initials of Washington, who, when a youth, 

 climbed up hither, and left this record of his adventure. We have several examples of 

 the disappearance of rivers, and their emergence after pursuing for some distance a 

 subterranean course. In these cases a barrier of solid rock, overlaying a softer stratum, 

 has occurred in their path ; and the latter has been gradually worn away by the waters, 

 and a passage been constructed through it. Thus the Tigris, about twenty miles from its 

 source, meets with a mountainous ridge at Diglou, and, running under it, flows out at the 

 opposite side. The Rhone, also, soon after coming within the French frontier, passes under 

 ground for about a quarter of a mile. Milton, in one of his juvenile poems, speaks of the 



" Sullen Mole, that runneth underneath ; " 

 and Pope calls it, after him, the 



" Sullen Mole, that hides his diving flood." 



The Hamps and the Manifold, likewise two small streams in Derbyshire flow in 

 separate subterraneous channels for several miles, and emerge within fifteen yards of each 

 other in the grounds of Ham Hall. That these are really the streams which are swal- 

 lowed up at points several miles distant, has been frequently proved by watching the exit 

 of various light bodies that have been absorbed at the swallows. At their emergence, 

 the waters of the two rivers differ in temperature about two degrees an obvious proof 

 that they do not anywhere intermingle. On the side of the hill, which is overshadowed 

 with spreading trees, just above the spot where the streams break forth into daylight, 

 there is a rude grotto, scooped out of the rock, in which Congreve is said to have written 



U 2 



