APPALACHIAN FOLDS OF CENTRAL PENNSYLVANIA 233 



mately symmetrical. The measurement then followed the base of 

 the Catskill to the end of the section (Fig. 5) . 



To follow and measure the contortions of these two selected forma- 

 tions throughout their length, a copper wire was used. Placed upon 



Fig. 3. — Reconstructed section between Lewistown and Durward 



Fig. 4. — Section between Durward and Aqueduct Station 



Fig. 5. — Continuation of section from Aqueduct Station to Harrisburg 



the plotted cross-section, this was bent so as to be exactly super- 

 imposed upon the line to be measured. This wire, when straightened 

 out and measured, represented very closely the length of the chosen 

 stratum along its tortuous course. As the cross-sections were plotted 

 on millimeter paper all measurements were made in that unit. 



