The Louisville and Portland Canal is about two miles in length; is intended for steamboats of the largest class, and to overcome a fall of 24 feet, occasioned by an irregular ledge of limerock, through which the entire bed of the canal is excavated, a part of it, to the depth of 12 feet, is overlaid with earth. There is one guard and three lift locks combined, all of which have their foundation on the rock. One bridge of stone 240 feet long, with an elevation of 68 feet to top of the parapet wall, and three arches, the centre one of which is semi-elliptical, with a transverse diameter of 66, and a semi-conjugate diameter of 22 feet. The two side arches are segments of 40 feet span. The guard lock is 190 feet long in the clear, with semicircular heads of 26 feet in diameter, 50 feet wide, and 42 feet high, and contains 21,775 perches of mason-work. The solid contents of this lock are equal to 15 common locks, such as are built on the Ohio and New-York canals. The lift locks are of the same width with the guard lock, 20 feet high, and 183 feet long in the clear, and contain 12,300 perches of mason-work. The entire length of the walls, from the head of the guard lock to the end of the outlet lock, is 921 feet. In addition to the amount of mason-work above, there are three culverts to drain off the water from the adjacent lands, the mason-work of which, when added to the locks and bridge, give the whole amount of mason-work 41,989 perches, equal to about 30 common canal locks. The cross section of the canal is 200 feet at top of banks, 50 feet at bottom, and 42 feet high, having a capacity equal to that of 25 common canals; and if we keep in view the unequal quantity of mason-work compared to the length of the canal, the great difficulties of excavating earth and rock from so great a depth and width, together with the contingencies attending its construction from the fluctuations of the Ohio River, it may not be considered as extravagant in drawing the comparison between the work in this and in that of 70 or 75 miles of common canalling. In the upper sections of the canal, the alluvial earth to the average depth of twenty feet being removed, trunks of trees were found more or less decayed, and so imbedded as to indicate a powerful current towards the present shore, some of which were cedar, which is not now found in this region. Several _fireplaces_ of a rude construction, with partially burnt wood, were discovered near the rock, as well as the bones of a variety of small animals and several human skeletons; rude implements formed of bone and stone were frequently seen, as also several well-wrought specimens of hematite of iron, in the shape of plummets or sinkers, displaying a knowledge in the arts far in advance of the present race of Indians.