especially adverted to by him in a printed circular, in 1832; also, by Prof. W. R. Johnson, in his letter, dated April, 1838, to the National Foundry Committee.

CHANGES AND VARIATIONS IN THE MINERAL CHARACTER OF COAL SEAMS.

In an appendix to the Stony Creek Report, already alluded to, the writer, who was familiar during twenty-five years preceding with precisely similar phenomena in the basin of South Wales, endeavoured to illustrate these parallel cases by a series of analyses both of American and Enropean varieties of coal. These details were derived from well known authorities. Following up the plan, we have prepared a table of at least eleven hundred analyses of coals in all parts of the world, as a fitting and elaborate illustration of the present work. These tables will be found at the end of this volume. The authorities cited are the following:

In Europe.-Mushet, Ure, Dufrenoy, Berthier, Thomson, Schafhæutl, Robin, Karsten, Ffyfe, Richter, Kirwan, Richardson, Murchison, Lyell, Varin, Baudin, Piot, Elie de Beaumont, Flachat, Logan, Liebig, Pelouze, Regnault.

In America.-Troost, Ducatel, Jackson, Hayes, Clemson, Ellet, Johnson, Frazer, Shepard, Olmsted, Bache, Silliman, Rogers, Booth, Lea, Renwick, Chilton, Boyé, Owen.

To all these we must especially add the highly comprehensive and instructive memoir of Prof. H. D. Rogers, in the Transactions of the Association of American Geologists, on the Appalachian Coal Fields. This paper is a rich contribution to American geology; and it is due to the writer thereof to state that his views on the subject of the transition from anthracite to bituminous coal had been stated through the medium of his public lectures, in 1837, and were more fully developed in 1843.

For local statistics we have frequent acknowledgments to make to the newspaper press, among which we are bound to name the Miners' Journal, and the Anthracite Gazette, of Pottsville; the Mining Journal, of New York; and the Commercial List and other leading journals of Philadelphia. From such prolific sources as Hunt's Merchants' Magazine, Hazard's Register, the American Almanac, &c., we have been permitted to glean many valuable details. To proceed :

That changes in the composition of the coal, from a partially bituminous state to that of anthracite, occur in other parts of the world, several instances will be found in these pages. Those of South Wales and of the Donetz coal-field in Russia, and on a smaller scale in several of the basins of France, are cases in point.

In like manner the flaming coals of the Auvergne and Bourbonnois basins, are shown to contain a complete series of dry coals with a short flame; of fat coals with short flame; of fat with long flame; and dry with long flame. Also, in the basin of Commentry, we find,

at some hundred metres of distance, and upon the same margin of that basin, the anthracite of Chambled, and the dry coal with long flame of Ferrières.*

The Schuylkill coal region possesses striking points of resemblance, although upon a somewhat different scale, to the great coal basin of South Wales. The latter is ninety-four miles long, and averages about fifteen miles in breadth. Of this elongated area, the western seventy-four miles consist of anthracite beds, with the exception of some partly bituminous seams on the south side of the basin. The remaining twenty miles, on the east, consist of dry bituminous coals, semi-bituminous coals, and steam coals; but, occasionally, the same section yields beds of coal of modifications of all these varieties.

The Schuylkill region is sixty-five miles long; extremely attenuated for eight or ten miles, at its western extremity, so as to be unproductive there to any important amount. For about eighteen miles out of the sixty-five, at its western prolongation, the quality of coal is of an intermediate character, like the steam coal of Wales. It then gradually passes to free burning anthracite on entering Schuylkill county, from Lebanon; and, still further east, to the hardest and purest anthracite. We have, elsewhere pointed out a similar passage from the extremes of each quality, like those in Russia, and we add that of the coal basin of St. Gervais, in Hèrault, France.

GEOLOGICAL MODELS.

In intimate connection with the physical and economic geology of the Schuylkill coal region, the author may be here permitted to advert to a species of illustration, for the first time introduced in America, by himself. In 1840, a geological model was constructed of the western half of the Schuylkill coal district and its vicinity, upon a scale of two inches to the mile. The area so represented comprises seven hundred and twenty-three square miles, or 460,800 acres, being in breadth sixteen miles, and in length forty-five miles. This model was first exhibited to the Association of American geologists and naturalists, at their meeting in Philadelphia, in April, 1841, to illustrate an address "on the most appropriate modes of representing geological phenomena."t

Dr. C. T. Jackson, in his first general report of New Hampshire, in 1841, also takes occasion to recommend, strongly, the process of geological illustration through the aid of models. He, however, states his regret at the expensive nature of such works, and the length of time requisite for their completion.‡

* Annales des Mines, Vol. I., 1842, p. 96.

† Silliman's American Journal of Science, Vol. XLI., p. 81, 1841. Also, Transactions of the Association of American Geologists and Naturalists, Vol. I., p. 81.

Report of New Hampshire, by Dr. C. T. Jackson, 1841, p. 36.

NOTE.-In Europe, geological models and models exhibiting lines of railroads, mines and harbours, and even estates, are much coming into use; although the frequency of employing so desirable a mode of representation is impeded by the heavy cost of such works. This objection applies with even stronger force in the United States, where capital is less abundant and where economy is indispensable.

We perceive by a paper read to the Institution of Civil Engineers, in London, "on the

II. MIDDLE ANTHRACITE DISTRICT.

FIRST SUBDIVISION.

THE SHAMOKIN COAL-FIELD.

In proportion to its magnitude, this is the richest and most regular of all the Pennsylvania basins. The coal seams are unusually abundant. The writer ascertained the outcrops of upwards of twenty, towards the centre of the basin, in 1847, and more remain to be developed. Some of these are of large size, one being twenty-seven feet; and one, much larger, is called the Big or "Mammoth Vein." Its maximum thickness is said to be here about fifty feet.

At Bear Gap, towards the western termination of this field, is a fine natural display of outcrops of all dimensions. Like all the anthracites in their progress westward towards the Susquehanna, their specific gravity diminishes, and they become softer. "The coal of the extreme western end of the basin visibly partakes of the characteristics of bituminous coals; it crumbles to some extent during combustion, and it contains carburetted hydrogen gas; this ingrédient constitutes nearly 1.11 part by weight of the coal of this locality.' A cubic yard of this coal, here, weighs one ton and seventy-three pounds. Specific gravity, 1.371.

At Shamokin, an immense quantity of coal occurs in the northern rise of the strata, which are here displayed in a double axis. The beds vary from five to eleven and a half feet in thickness, with the exception of the "Mammoth Vein," which consists, it is said, of sixty feet of coal of various qualities and degrees of purity. In general, the Shamokin coal has a white ash: it is a free-burning anthracite, of fair repute in the domestic market, and from the vicinity of Mount Carmel eastward; it is sufficiently hard for smelting iron. The large vein appears to be identical with that seen at Tamaqua, at the Swatara region, in the Wyoming coal-field, Beaver Meadow, &c. The direction of the Shamokin beds is N. 82° E.

Amount of coal sent to market from the Shamokin district, via a railroad of sixteen miles to Sunbury on the Susquehanna, for the nine years in operation, from 1839 to 1847, inclusive, 119,311 tons.

construction of geological models," by Mr. J. B. Denton, May, 1842, that the cost was stated at from 28. 6d. to 38. 6d. $0.60 to 75 cents per acre. Of course, the expense is influenced by the scale on which the mode is projected. As Mr. Taylor's model of the Schuylkill region contains 460,800 acres, it would amount to a considerable sum, even at one-fiftieth part of the above named prices.

Again, the author referred to, states that a model, showing the line of a railroad or canal, would cost ten pounds [£10,] per mile. There are about one hundred and seventy miles of canals and lines of railroads and projected railroads shown on Mr. Taylor's model. If these rates include all the preliminary expenses of surveys and the collection of details, they are perhaps not so greatly overrated.

Since writing the foregoing paragraphs we have seen the commencement of a model of the Shamokin and Mahanoy coal basins in Pennsylvania, and rejoice at the adoption of this excellent mode of representation.

We refer our readers to an article containing much information on the comparative value of different kinds of coal for the purpose of Illumination, by Andrew Fyfe, M. D., F. R. §. Jameson's Edin. Journal, Vol. XLV., pp. 37-49. Silliman's Journal, January, 1849, pp. 77-86; March, pp. 157-167.

*Pottsville Correspondent.

This coal is of the white ash species. We have seen an analysis, which assigns 89.99 as the proportion per cent. of carbon in the harder variety. There were sent to market in

1848,

1849,

1850,

1851,

1852,

1853,

Tons.

19,356

19,650

19,921

23,989

25,846

15,500

"Arrangements are making to smelt iron in the Shamokin basin with the coal and ore found there, where there are facilities for additional supplies from the rich ores of Montour ridge, for which coal could be exchanged. In fact, coal is now transported from the Shamokin basin to the iron works of Danville, distant thirty miles, the distance to the Wilkesbarre basin being fifty miles. Hitherto the latter region was depended upon for the supply of the various works at Danville, which required 200,000 tons annually."

Until the year 1854, no extensive mining operations had been undertaken in the Shamokin coal-field. At present very large preparations are in progress for the shipment of coal from this region, and another year will probably suffice to put the collieries lately commenced, in a condition to furnish great quantities of coal to the several markets. The various improvements by which the products of this basin will be brought to market, are either finished or are rapidly approaching completion. The total amount of coal shipped from this region during the six years from 1847 to 1853, inclusive, was 134,172 tons. This coal was transported to Sunbury over the Sunbury and Shamokin rail-road, at that time known by the name of the Pottsville and Danville Rail-road, but never entirely completed. The communication between Sunbury and Baltimore, was by canal via Havre de Grace. The following companies have been formed for the development of the Shamokin coal-field; where extensive arrangements and large investments have been made for the efficient prosecution of their business.

The Locust Mountain Coal and Iron Company, owning 6250 acres of land, a portion of which lies in the Mahanoy region. This company is constructing three coal-breakers, a steam saw-mill, and one hundred miners houses. It has an outlet by the Coal-run, Mine-Hill, and Sunbury rail-roads. (See the table of analysis.)

The Coal-Run Improvement Company, (adjoining the preceding,) owns 3000 acres, of which 2200 acres is coal land. Three collieries, with breakers, and fifty miners' houses, are in preparation. The Coal-run rail-road, ten miles long, is on this tract, and it has access.

Pottsville Correspondent.

to the New York, and Catawissa, and to the Philadelphia and Sunbury rail-roads.

The Green Ridge Improvement Company, owning 2500 acres, all of which is coal land. It will connect by a seven-mile track with the Philadelphia and Sunbury rail-road. It is constructing two large collieries and coal-breakers, and 100 miners' houses.

The Philadelphia and Sunbury Rail-road Company, owning 3000 acres, all of which is coal land.

The Locust-Gap Coal Company, owning 2000 acres, of which 1000 acres are coal land.

The Summit Coal Company, owning 2000 acres, of which 1000 acres are coal land.

The Furnace-Run Coal Company, owning 2000 acres, of which 1000 acres are coal land. The lands of this company are near the town of Shamokin.

The Big Mountain Improvement Company, owning 6000 acres, of which 2000 acres are coal land. The improvements are two collieries, two coal-breakers, and 100 miners' houses.

The Coal Mountain Coal Company, owning 1000 acres, all of which is coal land. This company has a capital of $375,000, and in twelve months will be working two collieries, one of which will have a breaker. The other is a hard coal, intended for iron smelting, in which large coal is used. In their second year this company expects to mine from 150 to 200,000 tons.

The Carbon-Run Improvement Company, owning 2000 acres, of which 1800 acres are coal land. Its improvements are two collieries, one large coal-breaker, and eighty miners' houses.

The Mahanoy and Shamokin Improvement Company, owning 2064 acres, of which 1200 acres are coal land. Outlet by the Tiverton rail-road to the Susquehanna.

The Zerbe's Run and Shamokin Improvement Company, owning 2234 acres, of which 1400 acres are coal land. Outlet by the Tiverton rail-road.

We refer our readers to a Report of Professor Henry D. Rogers, on the coal lands of the Zerbe's Run and Shamokin Improvement Company, 1850.

Messrs. Longenecher, Baumgardner and Helfenstein, owning 1800 acres.

Messrs. Helfenstein and Boyd, owning 500 acres.

Hon. C. W. Hegins Dewart and others, owning 250 acres.

There have been erected and now finished, or nearly so, within