38 



SCIENCE. 



[N. S. Vol. IV. No. 80. 



sented by 15 to 30 feet of black shale, and 

 the Carboniferous by about 350 feet of very 

 siliceous limestone. 



The peculiar structures which character- 

 ize the intensely folded belt of the Appa- 

 lachian Valley are highly developed in this 

 region. The sections show five well-marked 

 synclines west of the Ocoee rocks, with a 

 large number which are less distinct. They 

 are all nearly parallel, crossing the tract 

 in a northeast-southwest direction with 

 slightly curved axes. These synclines us- 

 ually have gentle dips on their western 

 sides and steep or overturned dips on their 

 eastern. In most cases adjacent synclines 

 are separated by thrust faults. Thus the 

 strata are broken into a large number of 

 narrow blocks which overlap each other, 

 the fault plains all dipping southeastward. 

 The principal mineral resources of the 

 region consist of iron ore, lead ore, lime- 

 stone, building and road stone, and brick 

 and tile clay. A small amount of hematite 

 or red fossil ore occurs associated with the 

 shales of the Eockwood formation. Also 

 considerable bodies of limonite occur, chiefly 

 along the great thrust faults which sepa- 

 rate the Chilhowee series from the valley 

 rocks. The lead ore is found in limestones 

 at the base of the Knox dolomite, and is 

 mined to some extent a few miles south of 

 Cleveland. 



FOLIO 21, PIKEVILLE, TENNESSEE, 1895. 



This folio, by Charles Willard Hayes, con- 

 sists of 3i pages of text, a topographic sheet 

 (scale 1:125,000), a sheet of areal geology, 

 one of economic geology, another of struc- 

 ture sections, and a final sheet giving a gen- 

 eralized columnar section of the district and 

 vertical sections showing the position and 

 thickness of coal beds. 



The quarter-degree covered by this folio 

 has an area of 980 square miles. Its south- 

 eastern corner is just within the great Ap- 

 palachian Valley, and its northwestern 



corner occupies a portion of the highland 

 rim of Middle Tennessee. It therefore ex- 

 tends entirely across the Cumberland Pla- 

 teau, whose level surface has here an ele- 

 vation of about 1,700 to 2,000 feet above 

 tide. The plateau is intersected by Se- 

 quatchie Valley, a narrow depression be- 

 tween wall-like escarpments which are par- 

 allel with the eastern escarpment of the 

 plateau. This remarkable valley is located 

 upon the westernmost of the sharp anticlinal 

 folds which characterize the great Appa- 

 lachian Valley belt. The western escarp- 

 ment of the Cumberland Plateau is ex- 

 tremely irregular, being deeply notched by 

 the streams flowing from its surface. 



The two most important peneplains of the 

 southern Appalachians are well developed 

 in this region ; the higher and older ap- 

 pears in the surface of the plateaus, and 

 the younger, about 1,000 feet below, forms 

 the hilltops of the Sequatchie Valley and 

 the surface of the highland rim. 



The larger part of the surface of the Pike- 

 ville quarter- degree is occupied by Carbon- 

 iferous rocks, the coal measures (Walden 

 and Lookout sandstones) forming the sur- 

 face of the plateaus, while the Bangor lime- 

 stone and Fort Payne chert occupy the 

 lower slopes of the escarpments and high- 

 land rim to the west. The underlying De- 

 vonian and Silurian formations are brought 

 to light by the steep folds of the Sequatchie 

 and Tennessee Valleys. The Devonian is 

 represented by fifteen feet of carbonaceous 

 shale which appears to be entirely conform- 

 able with the formations above and below. 

 Three Silurian formations are represented 

 on the map. The Eockwood, at the top, is 

 composed of sandstone and sandy shale in 

 the Tennessee Valley, but becomes more 

 calcareous toward the west, so that in the Se- 

 quatchie Valley it is a shaly limestone, and 

 on the next quarter-degree is indistinguish- 

 able from the massive Chickamauga lime- 

 stone below. 



