TENNESSEE 643 rivers, and surrounded on all sides by sub- carboniferous hills. The third is the moun- tain division of the coal; a plateau 2,000 ft. above the sea, 40 m. wide by 140 m. long, bounded E. by the valleys of the upper Ten- nessee and Holston rivers, and covered with a plate of carboniferous rocks, which is thinned and broken up into patches and mounds as it approaches the Alabama state line. The fourth district is the great valley of Knoxville or East Tennessee. It is a prolongation of the great valley of Virginia, the valley of the She- nandoah, and that of Harrisburg and Heading, Pa. Its rocks are mainly of Silurian age, up- turned and broken by enormous faults, which bring them against the coal. On its E. side rise the Unaka mountains and their continua- tions, forming a fifth district, the true prolon- gation of the Blue Ridge and South mountain range, extending laterally into North Carolina, and composed of rocks of the lower periods of the Silurian age, the equivalents of the slate rock, gneiss, and marble of western Mas- sachusetts and Vermont, and partly of "cal- ciferous sand rock " age. The most abundant and valuable minerals of Tennessee are coal, iron, and copper. The state is crossed by the great Alleghany coal field, which extends from Pennsylvania to Alabama. In Tennessee it is nearly coextensive with the Cumberland table land, and forms an irregular quadrilateral 71 m. wide at the N. end and 50 m. at the S. It covers about 5,100 sq. m. The amount of coal has been estimated at 42,127,360,000 tons. The production of the state in 1870, according to the federal census, was 3,335,450 bushels, valued at $330,498. In 1874 there were 12 mines in operation, producing about 10,000,- 000 bushels annually. Iron exists in four dis- tinct belts or areas. The eastern belt stretch- es across the E. part of the state, at the base of the border range of mountains, extending into Virginia on the northeast and Georgia on the southeast. The most abundant ore in this belt is the limonite, which occurs in Johnson, Sevier, Carter, and Blunt cos. There are also veins of magnetite and hematite ore, which will yield from 60 to 70 per cent, of metallic ores. There are five furnaces in this region, capable of producing about 15,000 tons annu- ally ; but owing to the lack of railroad facili- ties the amount produced does not exceed 10,- 000 tons. Iron ore containing oxide of man- ganese is abundant in Greene co., from which spiegeleisen is made. The dyestone belt skirts the E. base of the Cumberland table land, extending beyond the limits of the state on the northeast and southeast. In Tennessee it reaches from Chattanooga to Cumberland gap, about 150 m. ; it spreads out laterally from 10 to 20 m. into the valley of East Tennessee, and includes the Sequatchie and Elk valleys. The chief ore of this belt is a stratified red iron rock, highly fossiliferous, occurring in layers, and called at many points dyestone, being sometimes" used for dyeing. The ore is a va- riety of hematite, and yields from 50 to 60 per cent, of iron. There are four furnaces in this region. The Cumberland table-land belt of iron ore is coextensive with the coal field. The ore lies interstratified with shale, sand- stone, and coal. It is called clay ironstone, and is an argillaceous carbonate of iron. It is inferior in quality, producing rarely more than 30 per cent., and usually not more than 20 per cent, of iron, and has not been worked. The western iron belt crosses the state N. and S., and lies mainly between the central basin and the Tennessee river, though extending in some counties a few miles W. of the river. It is about 50 m. wide, and embraces an area of about 5,400 sq. m. But the ore is found in available quantities only at certain points called "banks," some of which are miles in extent, while others occupy only a few acres. Some of these banks have been worked for 80 years with no signs of exhaustion. The ore is a limonite or brown hematite, some of it being inferior in quality; in other places the yield of iron is from 40 to 55 per cent. There are 11 furnaces in this region, with a monthly capacity of about 4,230 tons. Tennessee has decided advantages for making iron, in the abundance, cheapness, and contiguity of ore and of fuel ; the disadvantages are distance from market and want of transportation fa- cilities. Valuable deposits of copper are found in Polk co. in the S. E. corner of the state, covering an area of 40 sq. m. The ore is smelted by two extensive companies at Duck- town, having 25 furnaces and employing about 900 hands. From 1865 to 1874 the larger of these companies produced 8,476,872 Ibs. of in- got copper. Tennessee is rich in marble, which is found in every part of the state, the va- rieties including black, gray, magnesian, fawn- colored, white, red, variegated, conglomerate, and breccia. Many quarries are worked. Lime- stone and other building stone abound in vari- ous parts of the state. Slate is common, but little of it is valuable. Several beds of mill- stone have -been found, the most notewor- thy being in Claiborne co. Hydraulic rocks abound in many counties, especially in Hardin, Wayne, Perry, Decatur, Warren, and Mont- gomery, and in Knox and McMinn cos. in East Tennessee. Lithographic stone of an excellent quality occurs in McMinn co. Granite of vari- ous shades of color, some of it rivalling the Scotch granite, is found in Carter co. ; and unakite, a greenish compact granite, in the Unaka mountains, being peculiar to that lo- cality. Deposits of potter's clay are found in East Tennessee, on the Knoxville and Ohio rail- road, and in the vicinity of the lower Tennessee river, in the counties of Hickman, Henry, Perry, and Wayne ; also in Montgomery and Houston cos. Some of this clay has been worked up into stone ware. There are numerous potter- ies, the largest being in Memphis, Nashville, and Knoxville. Kaolin is found in Carter co. Fire clay is found in Stewart and Houston cos.
