In the upper sections of the canal, the alluvial earth to the average depth of 20 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 _fire-places_ 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 also 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. The first stratum of rock was light, friable slate in close contact with the limestone, and difficult to disengage from it; this slate did not however extend over the whole surface of the rock, and was of various thicknesses from three inches to four feet. The stratum next to the slate was a close compact lime stone, in which petrified sea shells, and an infinite variety of coraline formations were embedded, and frequent cavities of crystaline encrustations were seen, many of which still contained petroleum of a highly fetid smell, which gives the name of this description of lime stone. This description of rock is on an average of five feet, covering a substratum of a species of cias limestone of a bluish color, embedding nodules of horn stone, and organic remains. The fracture of this stone has in all instances been found to be irregularly conchoidal, and on exposure to the atmosphere and subjection to fire it crumbled to pieces. When burnt and ground, and mixed with a due proportion of silicious sand, it has been found to make a most superior kind of hydraulic cement or water lime. The discovery of this valuable lime stone, has enabled the canal company to construct their masonry more solidly than any other known in the United States. A manufactory of this hydraulic cement or water lime is now established on the bank of the canal, on a scale capable of supplying the United States with this much valued material for all works in contact with water or exposed to moisture; the nature of this cement being to harden in the water, the grout used on the locks of the canal is already _harder_ than the _stone_ used in their construction.