Section of the Coal strata at the Salines on Kenawha

River, Ohio.

The strata, beginning at the deepest, are as follow:

1. Sandstone. Sixty feet thick.

2. Coal. Six feet thick. It is bituminous and is extensively worked for several hundred feet under the hills.

3. Bituminous Shale, and slaty shale, forty feet thick. This, both slate and shale, is filled with extinct species of plants. Every layer not more than the fourth, or the eighth of an inch thick, when separated, displays fresh im.

pressions of a variety of species, delineated on the face of the slate with the most exquisite beauty and perfection. Four or five species of the Palm tree, as many of Calamites, and several Equisetae, are among the number.

4. A thin bed of coal, twenty inches in thickness, resting on the shale and clay-slate. This is not worked.

5. Argillaceous sandstone rock, the upper stratified in thin beds, the lower in beds of fifteen or twenty feet in thickness. This bed is about 200 feet thick, and splits easily into building stones, for which it is much employed. It is a vast magazine of fossil plants.

6. Bituminous Coal. This bed is four feet thick, and is extensively worked.

7. Silicious Sandstone. The grains are coarse, and sharp, and the bed reposes on the coal without any intervening slate, or shale. 150 feet thick.

8. Bituminous Coal. The structure of this bed is slaty, and in burning it melts, and runs together, obstructing the current of air necessary to combustion, a fact noticed as being common to all the upper beds of coal deposites. This bed is four feet thick, and the slate or shale on which it rests contains many impressions of plants, chiefly of the arundinaceous and culmiferous tribes.

9. Silicious Slate, or lydian stone; color nearly black, and in strata from two to eight inches in thickness. The bed is six feet thick, and is so hard as not to be impressed with the best tempered steel instruments. The Aborigines manufactured this kind of stone into arrow heads and knives. This deposite has been traced more than forty miles.

10. Argillaceous iron ore, in nodules from three to six inches in diameter, imbedded in argillaceous, yellowish marl. Eight inches thick.

11. Silicious sandstone; color yellowish, grain coarse, with feeble cohesion. At this place this bed is eighty feet thick, but in other places it has a thickness of 150 feet. It

contains a vast number of fossil trees. The wood has been replaced with silicious matter tinged with iron. Sometimes whole trees with their roots and branches have been found.

Very few fossil shells, or animal remains of any kind, have been found in the Kenawha Valley.

It is intended that our descriptions and remarks thus far, should apply entirely to the several kinds of coal called bituminous, and which burn with more or less blaze. These kinds, known under the names Cannel coal, Slatycoal, Coarse coal, &c. are found only among secondary rocks, and it would be a useless expenditure of time and money, to search for them in any other situations. Dr. Macculloch thinks that bituminous coal does not exist below the old red sandstone formations.

Anthracite. This name, which is derived from the Greek, signifies merely, carbon or coal. It is called, in England, stone coal, and in Scotland, blind coal. In this country, where there are many extensive localities, it is distinguished by the names of the places whence it comes, as, Lehigh coal, Lackawana coal, Peach Orchard coal, &e.

Anthracite has been found in small quantities only, in any part of Europe but in this country it appears to exist in great abundance, and within the last ten years has come into such general use as an article of fuel, as in a good degree to supersede the use of wood for the warming of dwellings, in most of the sea-coast towns of the Northern States. These supplies come chiefly from Pennsylvania and New York, though this coal exists also in Massachusetts and Rhode-Island.

Anthracite is found among primitive and transition rocks, as mica-slate, clay-slate, and greywacke.

This mineral is distinguished from bituminous coal by its greater lustre and weight; by its hardness and conchoidal fracture, and by its burning without smoke, or blaze, or bituminous odor.

ORIGIN OF COAL.

It is now generally believed, by naturalists, that coal has originated from vegetables, though there are many

different opinions with respect to the modes in which the vast quantities of woody matter, required for this purpose, came together; and also with respect to the chemical changes which it underwent during its conversion into coal, as well as the nature of the agent by which this was effected. That coal originated from wood, appears to be proved by the fact that at the present day, parts of trees are found in a state of partial conversion into that substance. This is called wood coal, or lignite, and in some countries, is not an uncommon substance.

Near Cologne, in Italy, exists a great depository of this fossil, which extends many leagues, and is fifty feet thick. Its covering is a bed of gravel about twenty feet thick. Here trunks of trees partially converted into coal are common, and many of them are deprived of their branches, which would seem to indicate that they had been transported from a distance. Nuts, which are indigenous in Hindoostan and China, are found among this lig

nite.

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In wood coal" says Mr. Bakewell, " we may almost seize nature in the fact of making coal before the process is complete. These formations are of a far more recent date than that of common coal, though their origin must be referred to a former condition of the globe, when the vegetable productions of tropical climates flourished in northern latitudes. The vegetable origin of common mineral coal, appears to be established by its associations with strata, abounding in vegetable impressions-by its close similarity to wood coal, and lastly, by the decisive fact, that some mineral coal, in the Dudley coal field, is entirely composed of mineralized plants."

But though the vegetable origin of coal may be satisfactorily established, there is considerable difficulty in conceiving, by what process, so many beds and seams of coal have been regularly aranged over each other, in the same place, and separated by strata of sandstone, shale and indurated clay. It will perhaps tend to simplify this inquiry, if we examine a coal field of very limited extent, such as those which occur in small coal basins, called swilleys, and which are not more than one mile in length and breadth. It seems evident that these basins have once been small lakes or marshes, and that the strata have been deposited on the bottoms and sides, taking the concave form, which such depositions, under such circum

stances, must assume; and it is deserving of notice, that the stratum of coal, which in one of these basins, is a yard thick in the lowest part, gradually diminishes as it approaches the edges, and then entirely vanishes. This fact proves that the present basin-shaped position of the strata was their original one; and that the basin, at the period when the coal was deposited, was a detached lake or marsh, and not a part of the bed of the sea.— -Geology, p. 123.

It would seem from the above, as well as from other facts stated by geologists, that coal strata were formed in accumulations of water; but whether this was salt or fresh, it is difficult to determine. The shells found in some coal beds, according to the opinion of Mr. Conybeare, are those of salt water; but, on the other hand, the vegetable remains found in the same strata, are clearly those of the land and not of the sea. But the difficulty of distinguishing salt from fresh water shells, where the species are extinct, is well known. And it is also true, that some shell-fish belonging to the ocean, may gradually be inured to brackish water, and finally to that which is entirely fresh, and this too without any material change in the form or thickness of their shells. Hence any decision of this kind, founded on the appearance of a few shells merely, must always be extremely doubtful.

It would appear from the account of Dr. Hildreth of Marietta, Ohio, that beds of coal on the Muskingum river, in that state, have either been formed in the ocean, or that since their formation they have been submerged by salt water. "The lime rocks here," says he, "abound in fossil marine shells of the genera Productus, Terebratulæ and Spirifira, with Ammonites, and chambered shells, indicating that some of the coal deposites have been deeply submerged under the salt water since their formation; or that the vegetable materials, composing the coal had once floated in an ocean, and were precipitated by an accumulation of calcareous, argillaceous, and sedimentary materials collected on and about them, while floating."

Marine fossils," continues the author, "are found both above and below the coal, and sometimes deposites containing fresh water shells are intermixed, although they are not so common as they are nearer the Ohio river. Some of these fresh water fossils bear a striking resemblance to living species now found in our rivers.