704 GEORGE W. STOSE 



the base are siliceous banded beds and large " edgewise " conglomerate, 

 closely resembling the Conococheague formation. These have been 

 separated as a transition phase under the name Stonehenge member 

 of the Beekmantown. 



The best exposure of the formation in the Chambersburg quad- 

 rangle is adjoining the Chambersburg-Gettysburg pike, where the 

 following composite section has been measured by Mr. Ulrich and 

 the writer. 



Beekmantown Section, i Mile East of Chambersburg. 

 Base of Stones River containing fine limestone conglomerate and 

 laminar and oolitic chert. 



600 feet. Interbedded fine-grained pure limestones and magnesian limestones, 

 finely laminated in part and containing small quartz geodes. Porous 

 sandy chert near top. Dark layers near base, mottled by magnesian 

 material that weathers out, leaving pits and holes, contain numerous 

 gasteropods and ostracoda. 



375 feet. Alternating pure dove and gray limestones and magnesian limestones, 

 with layer of sandy chert. 



100 feet. Bluish to dove fine-grained fossiliferous limestone, at the base con- 

 taining rounded quartz grains. 



275 feet. Pink, fine grained marble, containing layers of milky quartz chert. 

 Gasteropods of the genus Ophileta, Maclurea, and Eccyliopterus 

 rather abundant. 



285 feet. Pure dove and blue, fine-grained limestone, with some pink limestones. 

 Contains fragments of Trilobites. 



145 feet. Fine-grained dove to dark-gray limestone with fine conglomeratic and 

 oolitic beds. Abundant chert in upper portion, in part oolitic and 

 conglomeratic. 



225 feet. Fine-grained light- to dark-gray limestone containing contorted 

 laminae of sandy matter, that stand in relief or fall to sandy 

 shale on weathering, and thick beds of "edgewise" conglom- 

 erate. Contain Gasteropods in upper portion and fine frag- 

 ments of Trilobites in lower part, 



260 feet. Dark- to light-gray limestone, with sandy laminae less developed 

 than in overlying beds. Contain Orthis, Ophileta, and Trilo- 

 bite fragments. 



Top of Conococheague, containing contorted sandy laminae and beds 

 of coarse limestone conglomerate. 



2,265 f^^t total. 



In the Mercersburg quadrangle an excellent section of the Beek- 



