Lesley.] 30 [May. 



57. Dr. Dunglison "svas appointed to prepare an obituary 

 notice of the deceased. 



Mr. Lesley announced the death of a member of the So- 

 ciety, Prof. K. C. Von Leonhard, at Heidelberg, on the 23d 

 of January, 1862, in the 83d year of his age. 



A memoir was presented for the Transactions by Dr. Hay- 

 dcn, and referred to a committee, consisting of Dr. Leidy, 

 Prof. Lesley, and Dr. Roehrig. 



Prof. Lesley exhibited a manuscript map of the Alleghany 

 Mountains on a large scale, and described especially the coal 

 formation of Southern Virginia. He remarked that : 



The coal region of Montgomery, Pulaski, Wythe, Washington, 

 and Smith counties in Southern Virginia, is interesting in an eco- 

 nomical as well as a geological sense. It furnishes species of semi- 

 antbracitc and semi-bituminous coal, which come in competition 

 with the Oolitic bituminous coal of the Richmond basin, over the 

 principal internal railroad of the Southern Atlantic States. This 

 railroad penetrates the great primary range of mountains, the Blue 

 Ptidge, at Lynchburg, and then follows the course of the Great 

 Valley, southwestward, to Knoxville and Chattanooga, in Eastern 

 Tennessee. This Great Valley, of Lower Silurian limestone, extends 

 from Newburg on the Hudson to Montgomery in Alabama, every- 

 where separating the range of the Blue Ridge, South Mountain, 

 Smoky Mountain, or Black Hills, from the true Alleghanies or Ap- 

 palachians. The rocks of the Blue Ridge Range, on the eastern side 

 of the Valley, are a prolongation of the Green Mountains of Vermont, 

 and consist of the Quebec group or Taconic system, now understood 

 by Logan to be a thickening of the lowest Silurians (Calciferous Sand- 

 rock and Potsdam Sandstone or Primal Slates).* The Appalachian 

 3Iountains on its western side are Middle and Upper Silurian and De- 

 vonian formations. West of these rises the long high escarpment of 

 the Carboniferous formation, forming the mountain plateau of Western 

 Pennsylvania, Western Virginia, Eastern Kentucky, Central Tennes- 

 see, and Northern Alabama. The escarpment of this vast plateau, 

 facing the east, and overlooking the Appalachian ranges, with their 

 narrow, parallel, interval valleys, is the so-called Backbone Alleghany 



* It is but just to say that the Rogerses maintained substantially this view be- 

 fore 1840, considering, as they did, the Blue Ridge System an enlargement merely 

 of Formation No. I. 



