CENTRAL COAL-FIELD IN INDIANA.
That portion of the Central coal-field lying in Indiana we have stated at 6700 square miles of productive coal-area. The coal formation is per haps filly 10,000 square miles in extent.
The maximum depth of the coal measures is greater than in Illinois, but less than in Kentucky. The number of workable seams is 6 in some localities with a total thickness of 35 feet; but generally only three seams are of workable size, and towards the edges of the field only one is found of workable dimensions. The upper cannel-coal seam of the Kanawha does not seem to exist; but the lower cannel is good and productive, and from 3 to 4 feet in thickness. The fracture is conchoidal and rather dull. It is heavier than ordinary cannel, weighing 75 pounds to the cubic foot, and contains Notwithstanding its conchoidal fracture when broken across, it parts readily in flakes, and burns without any tendency to coke or cake. Its
ready ignition, rapid combustion, and bright fierce flame render it a splen did fuel for Western steamboat use, in generating steam rapidly; but it is less durable than the harder bituminous of bed B,* which contains less bitumen and more carbon than any of the other workable beds in Indiana. The amount of workable coal in this part of the Central coal field may be stated at an average of 20 feet, distributed in from one to six seams. The amount of coal mined can only be approximated at present ; but it cannot be less than 500,000 tons annually.
Figure 130 is from Taylor's Statistics. We introduce it merely to convey an idea of the relative width in the lower end of the Central coal field and the progressive depreciation westward.