p. 18

-18-

1827.

Nearly all the rock is yet to be excavated. One stone arch bridge is yet to be built, where the turnpike crosses the canal. A pavement extending from the top of the rock to the top of the bank. Upon the whole it is considered about half completed.

As a cause of this backwardness of the contractors, perhaps it ought to be mentioned that there is a great difficulty in getting laborers in this part of the country and particularly in the summer season. One more year has been allowed by the legislature for the construction of this canal. But whether it will be completed within this time is a matter of some doubt.

Having thus completed my description of the canal, it may not be unacceptable to add such observations relating to the geology of the country about the rapids, as I have made, imperfect as they are they may have their use. Of the rock strata there are four:

1st. Limerock, probably the common compact lime rock, -as to the depth and extent of this rock I am unable to set any limits. It passes under the slate rock in the bank of the river below Shippingsport, but whether it rises again I do not know. It contains a great variety of Petrifactions. The minerals which I have collected from it are few and common,-the principal are quartz crystals, calcareous spar, and sulphuret of iron. Several springs issue through it, most of which contain a considerable quantity of Oxide of Iron held in solution by means of Carbonic Acid. This has induced many persons to ascribe valuable medical properties to them. When newly exposed to the air the rock continually gives out an agreeable bituminous odor, occasioned by petroleum or Seneca oil, which is found filling the cavities."

In some rare and small places this rock is composed of small six-

*First published notice of this important fact. H.W. Michell--P. 18 Am. [? 1894)