From the foregoing table it may seem that some objectionable features attend the location of the canal, such as the occurrence of contiguous locks in five places, the crossing of Fork Run and Dunlap's Creek by aqueducts, and the deep cuttings in the sixty-second level. The reasons which influence me in each instance will therefore be detailed. The levels along Fork Run, from the descent of its valley, necessarily had to be very short. The length of the first level was greater than could have been the average by single locks, and, to avoid contiguous locks, on that account alone we shoul have terminated it. But a single lock would have brought the next level in contact with unfavorable ground, necessitating either a circuitous route around a ravine or a3 embankment across it; and, to diminish the difficulty, we descended at once by two locks.

At the end of the third level the same reasons for five contiguous locks obtained, bat to a greater degree; the ground was exceedingly steep at the elevation at which we were above the stream, and a wider and deeper ravine was before us.

The seventh level was terminated by two contiguous locks, that the eighth level might occupy the most favorable ground, and the tenth level was terminated by fear contiguous locks to avoid a high and precipitous cliff of sandstone.

Thus far the left shore was the preferable one, but thence to the mouth of Fork R the right was decidedly better, because of the frequent occurrence on the left shore of steep and rocky ground. We therefore, on arriving at the end of the tenth level, descended, in order to cross as soon as possible; and to do so with the shortest and lowest aqueduct, we resorted to two locks. In the valley of Dunlap's Creek the descent from an upper to a lower level is only in three places effected by two contignos locks; in the first two cases, it was to shorten the distance to avoid very steep grous and to take advantage of very favorable flats; in the last case, it was to diminish the height of walling necessary to pass the cliff, which occurs in the seventy-first level. The reasons for crossing Fork Run in the nineteenth level have been already given in the second instance near the mouth. It was crossed to save the distance to a favor able point for crossing Dunlap's Creek above the mouth of Fork Run, to say nothing of the ground on the left shore of Dunlap's Creek being decidedly preferable to that va the right for nearly 2 miles.

Dunlap's Creek was then crossed, because the expense of crossing Brush Creek, Lack Creek, and sundry smaller runs which enter on the left, would, in itself, have bee more than the expense of crossing and even recrossing Dunlap's Creek; and, besides, the ground on the right for more than five miles was known to be much better thaa that on the left.

The canal subsequently crosses Dunlap's Creek four times in its progress to the mouth of the creek. The high and extensive cliffs which occur on the right shore b tween the fifth and seventh miles, it was thought, entitled the left shore to the prefer ence during that distance; but the entrance of Ogley's Creek just below the fifth and the continuance of very steep and rocky ground on the left, again renders a expedient to gain the right shore.

The last two crossings of the creek are incurred rather than wind around thạ bend of the stream, on the right of which there is a deep ravine, and very steep an rocky ground; and as, agreeably to your instructions, the canal was, if practicable. follow nearly the direction of the turnpike beyond that bend, one crossing, to avoid the rocky ground alluded to, necessitated another to conform to your instructions, since it was found practicable and altogether more expedient to follow the direction of th turnpike than the very circuitous course of the creek. In evidence of this fact the alternative, which is preferred, of crossing in the depression through which the tara pike is located, instead of following the valley of Dunlap's Creek, saves one thousand and thirty-three yards of canal along very unfavorable ground; at the expense, however, of the deep cut in the sixty-second level.

As to the termination of this subdivision, you remark in your instructions to e "Since it may reasonably be expected that, if ever a canal be made across the Alleghany Mountains to James River by the route to be surveyed, it would be contisse down the river, or the navigation of the river would be so far improved as to admit the passage of boats such as would be adapted to the canal, you will, to prov for either contingency, so conclude your survey on reaching James River that th length and height of an aqueduct to reach Covington may be determined, (as in the event of a continuation of the canal it is through that turn that the chief engineer of Virginia has recommended its location,) besides so locating it that in the event of its termination on this side, and the improvement of the navigation of the river by locas and dams, the lockage, &c., may be drawn to a basin on such a level as would be formed by the construction of a dam of some moderate elevation."

The location exhibited by the profile of the canal refers to the latter supposition, and the descent from the last level to the surface of a basin formed by a dam fee: high, two hundred and seventeen yards below the mouth of Dunlap's Creek, is supposed to be effected by a lock of 12 feet lift; the length of the dam is 300 feet.

On the supposition of an aqueduct to cross to the town of Covington, in order to

admit the requisite thickness to the arches and be beyond the reach of freshets, (which rise from 5 to 10 feet,) the seventy-first level should be continued across the river; the length of that level would be one mile and eight hundred and thirty-five yards, including an aqueduct 300 feet long and 21 feet high, counting from the bottom of the stream.

The heights of freshets in Dunlap's Creek vary, of course, with the fall and width of the stream, but they may be said to rise from 5 to 7 feet at most. The general depth of the stream is so trifling, that only the low-water mark has been represented on the profile; the height of aqueducts, walling, &c., is, however, counted from the bottom of the stream.

On reaching the valley of Dunlap's Creek, those considerations obtained which you directed in reference to the introduction of a supply of water from Dunlap's Creek without "the risk of inundation from freshets," the canal was dropped "so as to require but a short feeder from a suitable site for a dam of moderate elevation." The section of a dam on an enlarged scale is given on the map; the length of the feeder is but 610 yards.

THIRD SUBDIVISION.

From the western end of the summit-level to bench mark on the Greenbrier River. To this subdivision there is a table annexed, to comprehend precisely such facts as are contained in the table connected with the second subdivision.