and South Central Pennsylvania. 



409 



columns are arranged to best illustrate the paleogeog- 

 raphy of the province, starting with the Tyrone, Belle- 



Fig. 2. — The Middle Ordovician sections of central and south-central 

 Pennsylvania. 



The columns are numbered according to the locality numbers on Plate 

 1. For description of the symbols see the adjacent page. 



fonte, and Salona sections (Nos. 4, 5, 6), and extending to 

 the east as far as Reedsville (No. 13). The field evidence 

 suggesting this arrangement will be taken up under the 



