30 THE JOURNAL OF GEOLOGY. 



large area of quartz-porphyry in the Great Smoky Mountains in 

 Yancey Co., N. C, during the past summer. 



The geological reports on South Carolina, by Lieber, describe 

 a great development of igneous rocks which cross the state in 

 the continuation of the North Carolina volcanic belt and which 

 are themselves very probably in part of surface origin. His first 

 report for 1856, which treats of Chesterfield, Lancaster, Chester 

 and York counties, mentions among other more coarsely gran- 

 ular igneous rocks, eurite or quartz-porphyry, aphanitic-porphyry 

 and melaphyre.^ The counties of Union and Spartanburg, dealt 

 with in Lieber's second report, are much poorer in igneous rocks, 

 though he here adds the types schistose aphanite and minette. 

 On the geological map of South Carolina, published by the 

 Department of Agriculture in 1883, the belt of aphanitic green- 

 stones and porphyries is shown to be continuous across the state 

 in a southwest direction, and the statement is made that the 

 greenstones predominate toward the north, and the porphyries 

 toward the south, in Abbeville county. 



Upon an expedition undertaken at the instigation of the 

 writer, Prof. S. L. Powell of Newbury, S. C, found at Chester 

 abundant eruptive rocks (granites and diorites), but none of 

 unmistakably volcanic origin. At Lancaster, on the other hand, 

 he found amygdaloids and felsites, showing distinct flow-struct- 

 ures which are certainly of igneous origin and could only have 

 solidified at the surface. 



In Georgia and Alabama nothing can be stated with cer- 

 tainty in regard to ancient volcanic rocks as the crystalline 

 portions of these states have not as yet been petrographically 

 investigated. The porphyry area of Abbeville county, S. C, is, 

 probably continued into Georgia. One single specimen of quartz- 

 porphyry showing a beautiful micropoikilitic structure, collected 

 in northwestern Georgia near the Tennessee lirfe, has already 

 been mentioned by the writer.^ A box of specimens kindly sent 



' Report on the Survey of South Carolina for 1856, 2d ed., Columbia, 1858, p. 31. 

 Lieber had the German ideas regarding igneous rocks and their nomenclature. His 

 " trachyte," " domite " and " phonolite " are probably fine grained varieties of the 

 acid volcanic types. 



