764 ABSTRACTS 



Carboniferous, and the Lookout and Walden sandstones of the Coal 

 Measures. 



Alineral resources. — These consist of coal, iron ore, limestone, 

 building stone, and clay. The coal-bearing formations, the Walden 

 and Lookout, form the surface of the greater part of the district north- 

 west of the Cumberland escarpment, making a probably productive 

 area of 370 square miles. The Lookout always contains one and some- 

 times as many as four beds, all of which are locally though not gener- 

 ally workable. The upper bed, immediately below the conglomer- 

 ate, is the most constant. The greater part of the workable coal is 

 contained in the Walden, the lower bed probably corresponding to 

 the Sewanee seam farther west. This occurs in a belt six or eight miles 

 in width along the eastern edge of the plateau. The only iron ore 

 sufficiently abundant to be commercially important is the red fossil 

 ore, which occurs as a regularly stratified bed in the Rockwood forma- 

 tion. The numerous folds east of the escarpment bring the Rock- 

 wood to the surface in long, narrow bands, along which the ore has 

 been worked at many points. It varies in thickness from three to 

 seven feet, and although at some places it passes into a sandy shale, it 

 is generally a high grade ore. 



Geologic Atlas of the United States. Folio 6, Chattanooga, Tennessee, i8g4. 



This folio consists of three pages of text, signed by C. Willard 

 Hayes, geologist; a topographical sheet (scale i : 125,000), a sheet of 

 areal geology, one of economic geology, one of structure sections, and 

 one giving columnar sections. 



Geography. — The map is bounded by the parallels 35° and 35° 30' 

 and the meridians 85° and 85° 30'. The district is wholly within the 

 State of Tennessee, embracing portions of Bledsoe, Rhea, Sequatchie, 

 Marion, Hamilton, and James counties. It lies partly in the great 

 Appalachian Valley and partly in the plateau division of the Appala- 

 chian province. Its surface is marked by two distinct types of topogra- 

 phy, the plateau and the valley. The former prevails in the western 

 half of the district, which is occupied by portions of the Cumberland 

 Plateau and Walden Ridge, the two plateaus being separated by 

 Sequatchie Valley. The Cumberland Plateau has an altitude of about 

 2100 feet, with a level or rolling surface. Walden Ridge has an alti- 

 tude of 2200 feet along its western edge, and slopes gradually eastward 

 down to 1700 feet. Both plateaus are bounded by abrupt escarpments 



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