SOUTHERN AND CENTRAL APPALACHIANS 



121 



i 



j Fig. 8.29. Map of part of the Blue Ridge and Piedmont provinces of western North Carolina, 

 | showing the distribution of ultrabasic igneous rocks. After P. B. King, 1950a. Stippled areas 

 I are those of sedimentary rocks, mainly Paleozoic, but including the Ocoee series, probably Pre- 



Other less well-defined groups of intrusives occur toward the southwest 



edge of the metamorphic and plutonic belt, as near the inner margin of 

 1 the Coastal Plain in Georgia. The age of the ultrabasic intrusives in the 



southern Appalachians is unknown. Pratt and Lewis, on very tenuous 

 f evidence, conclude that they are of older Paleozoic age (King, 1950b). 



See Fig. 8.29. 



J Crystallines of Maryland and Southern Pennsylvania 



The Piedmont of Maryland and southern Pennsylvania merits special 

 j attention because of the considerable detailed work done there by Ernst 



Cambrian, and Brevard schist of unknown age. Blank areas east of, and within, stippled area 

 are those of gneiss and schist with bodies of intrusive granite. Small black areas are ultra- 

 basic igneous rocks. Heavy lines are faults. After P. B. King, 1950a. 



Cloos, students, and colleagues. Cloos (1953) has divided the region into 

 twelve divisions or zones, the first being the Coastal Plain. See map, 

 Fig. 8.30. The second division is the belt of most intense metamorphism 

 of the Piedmont province (Wasserburg ct ol, 1957) and contains a 

 number of gneiss domes. Six of these are in the vicinity of Baltimore and 

 their cores are made up of gneiss and migmatite (Baltimore gneiss) 

 which are mantled by the metasedimcnts of the Glenarm series (Tilton 

 et at, 1958). The lowest formation of the Glenarm is the Setters quartzitc, 

 the next above the Cockeysville marble, and the last the Wissahickon 



