340 E. B. MATHEWS SUBMERGED ^'dEEPs'' IN SUSQUEHANNA RIVER 



beyond this fact, that near its upstream end there is a subordinate de- 

 pression, about 25 feet below the normal profile of the hole, which makes 

 tlie upstream gradient of the depression less than that of the downstream. 

 The rocks along the bank are micaceous and chloritic schists and 

 gneisses in which the schistosity strikes north 70° east and dips 30° 



Sheet «3T 



^^ Susf^ehanna 



'G' 



Fiver 



^C> 



/Vote F/e^-at>ons in /keT odo^e Af.S.L, 



FicrRK 4. — Map of "Deep" at Holtivood, Peuusijlraiiia 

 Scale : 1 inch = 1,000 feet 



downstream. They show no noticeable differences in resistance to ac- 

 count for the depression. In the narrows above McCalls Ferry the banks 

 rise abruptly for 400 feet above the river, but the crest of the harder ridge 

 does not conform to the strike of the rocks, since the western rampart 

 lies upstream. The extension across stream on the strike of the rocks 

 shows side valley opposite promontory, and the reverse and not a strike 

 ridge cut by the river. 



