GEOLOGY AND MINERALS. The outcrops of the geological formations of Tennessee correspond with the topographical regions described above. In the western three-fourths of the State the strata lie nearly horizontal and undisturbed, and the Central Basin and Cumberland Plateau are formed by the wearing away in the one case of the overlying, and in the second case of the sur rounding portions of the strata. East of the Cumberland Plateau the strata are upturned so that their exposed edges form the ridges of the East Tennessee Valley and the mountain ranges. The great eastern Arch:ran area comes but slig,ht ly within the State limits in the extreme east. The Unaka Mountains are mostly of the Ocoee formation of the Cambrian system. The minor ridges and depressions of the East Tennessee Valley consist of successive outcrops of Potsdam sandstone of the Cambrian, and Trenton lime stone, shales, and dolomite belonging to the Lower Silurian age. The Lower Silurian strata pass under the Cumberland Plateau and High land Rim, and reappear as the surface rock of the Central Basin. and again in the bottom of the Western Tennessee Valley. The plateau strata are Carboniferous, the Highland Rim being Sub Carboniferous, while the Cumberland Plateau belongs to the Upper Carboniferous system. West of the Western Tennessee the Paleozoic strata disappear, and on their edges the Cretaceous and Tertiary strata rest unconformably. The Cretaceous outcrop is narrow, the greater part of the Western Plateau Slope being Tertiary. Be tween the bluffs and the Mississippi River the surface is of recent alluvial formation.
There are two great iron belts in the State, one occupying the western part of the Highland Rim, and the other stretching along the west ern slope of the Unaka Mountains. The ore is
chiefly limonite, with some magnetite in the northeast. Copper occurs in the metamorphic rocks in the extreme southeastern corner of the State. and zinc and lead are found in various parts of the East Tennessee Valley. The coal measures of the Cumberland Plateau contain sev eral scams of bituminous coal of workable thick ness. Other minerals of importance are hy draulic limestone and marble of a good quality, as well as other building stones derived chiefly from the Silurian strata.
MINI:vo. Tennessee is beginning to acquire considerable importance as a mining State. Coal is excavated in the mountain counties west of the Upper Tennessee River. For several years prior to 1S99 the annual value of the coal output was about $2.300,000; subsequently it rose until in 1901 it was valued at $4,067,381, the amount being 3,633,290 short tons. Over 9000 men are employed. There were 404.017 short tons of coke manufactured in that year. The iron ore mined in 1901, 789,494 long tons, was an increase over former years and made the State sixth in rank. Of the total amount, 474,545 tons was brown hematite. The mining of phosphate rock began in 1894 and the output of 1901 was worth $1,192, 090, which was less than in the previous year. The marble quarried in the State each year is usually worth between $300,000 and $400,000; in 1901, however, the amount rose to $494,637. The value of limestone quarried for that year was $330.927, a sum larger than usual. Clays found in the State are extensively utilized in the manu facture of brick and tile.