Near by are quarries of Breccia marble--a conglomerate of cemented variegated pebbles--out of which were cut the rich pillars in the House of Representatives at Washington. The Monocacy is crossed, near whose bank lies the bucolic old Maryland town of Frederick, to attain which a twig of the road wanders off for the few necessary miles. Soon the piquant charms of Potomac scenery are at hand, the mountains are marching upon us, and the road becomes stimulating. A jagged spur of the Blue Ridge, the Catoctin Mountain, strides out to the river, and the railroad, striking it, wraps itself around the promontory in a sharp curve, like a blow with the flat of an elastic Damascus sword. The broad Potomac sweeps rushing around its base: it is the celebrated Point of Rocks. The nodding precipice, cut into a rough and tortured profile by the engineers, lays its shadow to sleep on the whizzing roofs of the cars as they glitter by, (Shadows always seem to print themselves with additional distinctness upon any moving object, like a waterfall or a foaming stream.) There are a village and a bridge at the Point, and the mountain-range, broken in two by the river, recovers itself gracefully and loftily on the other side. [Illustration: POTOMAC TUNNEL, NEAR HARPER'S FERRY.] For half an hour more, as we rush to meet the course of the Potomac, the broad ledges that heave the bed of the river into mounds, and the ascending configuration of the shore, seem to speak of something grand, and directly we are in the cradle of romance, at Harper's Ferry. To reach this village, perhaps the most picturesque in the country, we must cross the Potomac from Maryland into Virginia. The bridge is peculiar and artistic. It is about nine hundred feet long; its two ends are curved in opposite directions, and at its farther extremity it splits curiously into two bridge-branches, one of which supports the road running up the Shenandoah, while the other carries the main road along the Potomac. The latter fork of the bridge runs for half a mile up the course of the Potomac stream over the water, the road having been denied footing upon the shore on account of the presence there of the government arsenal buildings. The effect to the eye is very curious: the arsenal is at present razed to the level of the ground (having been fired, the reader will remember, by the Federal guard at the beginning of hostilities, and some fifteen thousand stand of arms burnt to prevent their falling into Lee's hands), and there is no topographical reason to prevent the track running comfortably on dry ground. The arrangements, however, for purchasing the right to a road-bed on the arsenal grounds, though under way, are not yet complete, and the road marches on aquatically, as aforesaid.