Ii881.] -^ly [Stevenson. 



A Geological Reconnaissance of Parts of Lee, Wise, Srott and WasMng- 

 to?i Counties, Virginia. By John J. Stevenson, Professor of Geology 

 in the University of the City of New York. ( With six wood cuts and a 

 colored map.) 



{Bead before the American Philosophical Society, January 21, 1881.) 



Introduction. 

 I. General structure of the area ; description of the faults. 

 II. General description of the several groups. 



III. Geology of the area drained by Powell river. 



IV. Geology of the area drained by Clinch river. 

 V. Geology of the area drained by Holston river. 



In a former memoir,* the writer described a small part of Lee and Wise 

 counties, and gave some casual observations respecting a part of Scott 

 county. Examination of a larger area has shown that two serious errors, 

 due to too ready acceptance of information respecting localities not visited, 

 occur in that memoir, and has led also to a change in opinion respecting 

 the structure of Stone mountain. 



The counties examined occupy the extreme south-west corner of Vir- 

 ginia ; Lee being in the angle between Kentucky and Tennessee, with 

 "Wise adjoining it along the Kentucky line, while Scott and "Washington lie 

 next along the Tennessee border. 



The surface is broken by rudely parallel mountain ranges, separated by 

 narrow valleys. The distance along the shortest line from the city of 

 Bristol to the Kentucky border is barely fifty miles, yet in following that 

 line one must cross Walker, Brushy and Clinch mountains ; Moccasin, 

 Copper and Buckner's ridges, Powell mountain, Wallen's and Poor Valley 

 ridges, Stone and Black mountains. Several of these ridges are single, and 

 have abrupt shapes, while others are compound, and their slopes afford 

 grades not too difficult for wagons. 



The area between the Great Valley of Virginia and Moccasin ridge is 

 drained by the Holston river ; that between Moccasin ridge and Powell 

 mountain, by Clinch river ; and that beyond Powell mountain to the Ken- 

 tucky line, by Powell river. The Clinch and Holston unite to form the 

 Tennessee river, and Powell river enters the former at not far from Knox- 

 ville. Of these rivers, the Powell rises within the area examined ; the 

 others have their sources far beyond toward the north-east. 



A narrow strip of this region along the Kentuck}'- border has been ex- 

 amined by Mr. P. N. Moore, of the Kentucky Geological Survey, and a 

 summary account of his observations is given in the reports of that Survey, 

 Vol. IV. Prof. Lesley's work, as described in his memoir, f is slightly 

 overlapped by the writer's examination. The whole region was examined 

 during the survey under Prof W. B. Rogers. One is compelled to regret 



* Read before this Society, August 20, 1880. 

 t Proceedings of this Society, 1872. 



PKOC. AMER. THILOS. SOC. XIX. 108. 3b. PRINTED FEBRUARY 31, 1881. 



