760 ABSTRACTS 



of strata. Between Blue Ridge and Catoctin Mountain the Algon- 

 kian or oldest rocks appear on a great anticlinal uplift, with Cambrian 

 rocks on either side. Faults appear chiefly on the west side of this 

 uplift, and metamorphism increases toward its side. In Shenandoah 

 Valley the rocks are folded to an extreme degree, and the strata are 

 frequently horizontal or overturned. The Juratrias rocks always dip 

 toward the west, and are probably repeated by faults different in nature 

 from the Appalachian faults. In the sheet of sections the details of 

 the folds and faults appear. 



Economic products of this region comprise copper and iron ore ; 

 ornamental stones, such as marble, limestone conglomerate, and amyg- 

 daloid ; building stones, such as sandstone, limestone, and slate; and 

 other materials like lime, cement, brick-clay, and road materials. The 

 localities of each of these materials are noted and quarries located on 

 the economic sheet, and the character and availability of the deposits 

 are discussed. 



Geologic Atlas of the United States. Folio 2, Ringgold, Georgia, Ten- 

 nessee, i8g4. 



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

 geologist; a topographic sheet (scale 1:125,000), a sheet of areal 

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

 giving columnar sections. 



Geography. — The district of country covered by this folio lies 

 mainly in Georgia, a narrow strip about a mile in width along its 

 northern border extending into Tennessee. It embraces portions of 

 Dade, Catoosa, Walker, Whitfield, Chattooga, Floyd, and Gordon 

 counties in Georgia, and of Madison, Hamilton, and James counties 

 in Tennessee. The region forms a part of the great Appalachian Val- 

 ley. Its surface is marked by three distinct types of topography viz.: 

 plateaus, formed by hard rocks whose beds are nearly horizontal ; 

 sharp ridges, formed by hard rocks whose beds are steeply inclined ; 

 and level or undulating valleys, formed on soft or easily eroded rocks. 

 The plateaus are confined to the western third of the district, and 

 include portions of Lookout and Sand mountains. Their surface is 

 generally level or rolling, with a slight inclination from the edges 

 toward the center, giving the plateaus the form of a shallow trough. 

 They are bounded by steep escarpments rising from 1000 to 1200 

 feet above the surrounding valleys. The sharp ridges are confined to 



