GEOLOGICAL SOCIETY OF PENNSYLVANIA. 315 



1- Stratified rocks, partly oA'^erlaid by hori- 

 zontal secondary beds, . . . 10 miles 



2. The Gold Belt — talcose slates, protogine 



and quartz veins, . . . . 11 " 



21 " 



This series comprises rocks of innumerable variety in 

 their mineral constituents, dipping seldom more than 10° 

 from the perpendicular^ towards the south east. 



II. Zone of Modified and Mixed Rocks allied to the 

 Primitive. — Extending from the Gold Belt towards the 

 western base of the Blue Ridge, 36 miles. 



This class is described as containing an infinite variety 

 of amphibolic aud epidotic rocks and trapites, including 

 also, within its limits, some bands of sienite. talcose slates, 

 and innumerable quartz veins, which have not yet been 

 determined to be auriferous. 



Their inclination is remarkably uniform, being from 

 8 to 15° from verticality. 



III. IVamition of later date than the preceding. — A 

 part only of the breadth of the great Winchester lime- 

 stone valley, 14 miles. 



The inclination of whose beds is from 30 to 45° from 

 the vertical, and is somewhat disturbed and obscure near 

 its junction with the Blue Ridge. 



IV. Secondary. — Occupies a breadth on this section of 

 seven miles, partly covering the primitive rocks, and 

 therefore included in the length of Class 1. 



Horizontal apparently. 



Total length of this section 71 miles, at right angles 

 to the courses of the beds. 



The only geological document extant with which we 

 can compare our sections, is the map of Mr M'Clure, 



