July 10, 1896.] 



SCIENCE. 



35 



geologic history of the Appalachian province 

 is presented in outline, and the local rock 

 groups are fully described in regard to com- 

 position, thickness, location, variety and 

 mode of deposition. The formations range 

 in age from Algonkian (?) to Silurian, the 

 greater portion being Algonkian (?) . The 

 Silurian rocks appear in the East Tennessee 

 Vallej^, the Cambrian in Chilhowee Moun- 

 tain and in various narrow belts in the val- 

 ley, and the Algonkian southeast of Chil- 

 howee Mountain. The Algonkian rocks are 

 chiefly slates, sandstones, conglomerates and 

 graywackes ; the Cambrian rocks consist of 

 sandstones and shales in the Chilhowee 

 belt and of sandstones, shales and lime- 

 stones in the valley ; the Silurian rocks 

 comprise sandstones, limestones and shales. 

 The details of the series of strata are shown 

 in the columnar section. The process of 

 decay in each kind of rock is discussed, and 

 the manner in which the residual soils and 

 forms of surface depend on the nature of 

 the underlying rock. 



In the discussion of ' Structure,' after a 

 general statement of the broader structural 

 features of the province, two methods are 

 shown in which the rocks have been de- 

 formed. Of these the extreme Appalachian 

 folding is the chief, and less in importance 

 are the broad vertical uplifts. Three de- 

 grees of deformation appear in the Paleo- 

 zoic rocks — folding, faulting and metamor- 

 phism — each being best developed in certain 

 kinds of strata. The region northwest of 

 Chilhowee Mountain is broadly anticlinal, 

 while the Smoky Mountain district is syn- 

 clinal, and two lines of minor uplift appear 

 in each of these districts. Faults are found 

 chiefly on the west side of these minor up- 

 lifts, especially in the Cambrian sandstones, 

 and metamorphism increases southeast from 

 Chilhowee Mountain. In the East Tennes- 

 see Valley the rocks are folded to an ex- 

 treme degree and the strata are frequently 

 perpendicular or overturned. In the sheet 



of sections the details of the folds and faults 

 appear. 



Economic products of this region com- 

 prise gold and iron ore, ornamental stone, 

 such as marble, such building stone as sand- 

 stone, limestone and slate, and other mate- 

 rials, like lime, cement and brick clay. The 

 localities of each of these materials are 

 noted, and quarries are located on the eco- 

 nomic sheet, and the nature and availability 

 of the deposits are discussed. The resources 

 of the region which inhere in timber and 

 water power are also described. 



FOLIO 19, STEVENSON, ALABAMA-GEORGIA- 

 TENNESSEE, 1895. 



This folio, by Charles Willard Hayes, is 

 bounded by parallels 34° 30' and 35° and 

 meridians 85° 30' and 86°. It contains 980 

 square miles, embracing portions of Frank- 

 lin and Marion counties in Tennessee ; 

 Dade, Walker and Chattooga in Georgia ; 

 and Jackson, Dekalb and Cherokee in Ala- 

 bama. The folio contains four pages of 

 text, including a generalized columnar sec- 

 tion and four coal sections; one sheet show- 

 ing topography, another showing areal ge- 

 ology, a third economic geology and a 

 fourth giving five structure sections in- 

 serted in the map. 



The Stevenson quarter degree is occupied 

 chiefly by the Cumberland plateau and its 

 outliers. Sand and Lookout Mountains. It 

 includes also a portion of Brown's Valley, 

 which is the southward continuation of Se- 

 quatchie Valley and is located upon the 

 westernmost of the sharp anticlines which 

 characterize the folded belt of the Appa- 

 lachians. Extending diagonally across the 

 center of the area is a broad, level plateau, 

 forming Sand Mountain. It is bounded by 

 straight and steep escarpments. To the east 

 are Lookout and Wills valleys, also located 

 upon sharp anticlines. Finally, the south- 

 eastern portion of the area is occupied by 

 Lookout Mountain, also a broad, level pla- 



