SKETCHES OF LOUISVILLE.

GEOGRAPHICAL MINERALOGY.

In attempting a sketch of the Mineralogical Geography of the surrounding country it is necessary to premise, that although the rock throughout the whole of it belongs to the floetz limestone, being a portion of one of the largest formations of that description in the known world, yet such is the irregularity of its appearance that a correct idea cannot be entertained of it, by confining ourselves to an examination, at any one particular point. In the prosecution of this subject therefore, we will begin with sub-stratum, visible at the lower end of the Indian Chute in the rapids, and endeavor to give as correct an account as possible of the superincumbent ones, as they are found in the immediate vicinity of the falls, subsequently noticing those of the higher portions of the same low tract, and conclude with the higher country, which has an elevation of 600 feet above the former.

The lowest or first stratum then, of which we have any precise knowledge, is a sheet of Limestone of a bluish grey colour, imperfectly crystalized, of an average spec. gravity of 2.67, which furnishes but indifferent lime, valuable however for building purposes, remarkable for containing vast numbers of some unknown fossil*, and being the principal bed of that enormous quantity of Brain Stonest spoken of hereafter. It rises 10 feet above low water mark, to what depth it extends below is unknown.— Succeeding this we have one of a very different aspect and texture; it is of an ashy grey colour, a specific gravity of 2.65, fracture perfectly conchoidal and earthy, presenting no marks of crystalization whatever, penetrated by minute schistose particles, and extremely friable if exposed to the air for any length of time, in which case, it spalls off, and finally crumbles into pieces of a few pounds weight. It contains but very few marine exuvia, and is equally useless for either building or paving.

Covering the latter, we find a third stratum of a close grained compact limestonet, fre*Vide chap. on organic fossil remains. †Madrep. Cerebrum. The lapis suillis.

quently containing transparent rhomboidal calcarious crystals, and occasionally cubic ones of sulphate of lime: It is of a bluish colour, specific gravity 2.68, and is filled with fossils of various descriptions, the rock in many instances appearing to be formed of nothing else. These two last strata, are split in every direction, the fissures being filled with an indurated petroleum, which is not unfrequently found to interpose between the different sheets, cementing them together. In the upper one, cells are sometimes seen, in which are found from one to two ounces of the same substance in an oily form.

A stratum of aluminous Schist, next makes its appearance, of from 4 to 6 feet in thickness, as viewed from the banks of the river, (whose bed it forms below the rapids) that stretches out north and south from the Ohio into the Knobs and Silver Creek Hills, constituting their basis and that of the adjacent high country. It is very bituminous, frequently contains soluble pyrites, and if thrown upon a fire burns with rapidity, yielding considerable heat. Impressions of leaves, and of a plant of the Fera family are commonly observed in it.

Resting upon this slaty bottom we have an alluvial formation consisting of various depositions, the first of which is a bed of blue, and in some places a deeply coloured yellow clay, that is laid immediately on the Schist: the second, a loose sand, disposed in a waving position, in which water is found so plentifully as to prevent the inhabitants from sinking their wells deeper in search of it; the third a yellow clay, which is covered in its turn by sand similar to the former, the whole being crowned with rich loam ten feet in depth.

Such were the appearances presented by the first bank, or bottom, (front of and a little below Louisville on which Shippingport is built,) in digging the foundations for Mr. Tarascon's mill. They vary however considerably from those, exhibited on the route of the contemplated canal, which runs but few hundred yards from it, by the shafts,that were left open for some time to public observation. Throughout the whole of its track, but two strata one of yellow clay mixed with fine sand, the other, a blue clay, mixed with the same material, are found to intervene between the loam on the surface and the rock below.

This irregularity extends to the second bank, where we find alternate and various strata of sand and clay, until we arrive at the depth of 40 feet, where there is always found a bed of gravel, composed of water worn pebbles, presenting specimens of all the various rocks both primitive and secondary, that compose the Allegheny, Appalachian, Cumberland, Clinch and Gauley mountains, such as, Granite of various kinds, Kneiss, Trapp, Hornblend, Schorl, Sennite, &c.

If we now take a view of the higher portions of this same low tract, we may observe, as on the banks of Harrod's Creck, a vast body of a spongy light cellular limestone, indeterminately stratified, at least 100 feet deep, that is fissured in every direction, and penetrated by a number of perpendicular holes resembling wells, and below this a regularly stratified lime-rock, containing a number of fossils, some few of which are found in the upper one.

The latter appears to be in a constant state of decomposition, as the surface of it is covered with a soft calcarious earth, which if removed, speedily forms again.

On the Kentucky river near Frankfort, we