702 GEORGE W. STOSE 



limestone pebbles, i inch or more in size, in a matrix containing 

 numerous round coarse grains of vitreous quartz ; the other is com- 

 posed of long slender fragments of Hmestone in a calcareous matrix, 

 which, because the fragments are tilted at various angles, is called 

 "edgewise" bed. Interbedded with the conglomerates are oolites and 

 dark shaly limestones with red clay partings. 



The body of the formation is a closely banded dark blue limestone, 

 the bands varying from one-half inch in width to minute laminae. 

 The banding is inconspicuous in the fresh rock but is brought out 

 in weathering as yellowish sandy streaks across a light-blue or gray 

 surface. Toward the top these partings become more numerous 

 and sandy, and weather into hard sandy plates and sheets. Chert 

 is not an important constituent of the formation in the Chambersburg 

 and Mercersburg quadrangles. 



The thickness of the formation is about i,6oo feet. 



A section measured at Scotland is as follows : 



Rather pure, light, shelly or platy limestone, probably Beekmantown- 

 90 feet. Granular crystalline limestone containing coarse "edgewise" con. 

 glomerate, oolite, and pink marble, with numerous slaty partings 

 weathering to glistening shale particles. 

 300 feet. Covered. 

 15 feet. Fine-grained, pure, light limestone, "edgewise" conglomerate and 

 cross-bedded limestone containing quartz grains 

 390 feet. Covered. Lower portion contains impure dark Hmestone and large 

 banded chert. 

 10 feet. Banded, dark and light limestone. 

 270 feet. Dark, rather pure limestone containing trilobites and oolite, with 



argillaceous partings weathering to soft shale or slaty partings. 

 40 feet. Massive light-colored, dense, even-grained limestone, with few fluted 



siliceous partings. 

 70 feet. Covered. 

 180 feet. Corrugated impure siliceous banded limestone and hackly shaly 



limestone. 

 30 feet. Dense, black, rather pure limestone. 

 40 feet. Massive beds of crumpled, siliceous banded limestone. 

 200±feet. Dense siliceous banded limestone with "edgewise" conglomerate, 

 cryptozoan, and sandstone beds at the base. 



1635 feet, total. 



The Conococheague limestone occurs in a broad sinuous belt 

 crossing the Chambersburg quadrangle from south to north. It is 

 plicated into many folds northwest of Waynesboro, marked by ridges 

 of rough topography, and just south of the Chambersburg pike its 



