PHYSICAL GEOGRAPHy'oF THE COUNTY F 3 . 19 



flows Fishing creek, passes Keystone and Marysville to the 

 Susquehanna river. 



Itivers, Creeks, and Runs. 



The Susquehanna river flows in a shallow rocky channel, 

 about half a mile wide, studded with islets, along the eastern 

 border of the county, a distance of about 20 miles in a 

 straight line, but of about 30 miles by its windings from 

 north to south. 



These windings are caused by the topographical ob- 

 stacles which it encounters. Within three miles of the 

 county corner it is deflected sharply westward along the 

 north foot of Buffalo mountain, 3 miles to Liverpool, where 

 it gets through the mountain by a boldly cut gap. 



Cutting straight across the Hunters run cove 3 miles, and 

 issuing from a similar gap in Berry's mountain, it is de- 

 flected a little east around the end of Half Falls mountain. 



Bending west again in a beautiful quadrant of a circle 

 past Xew Buffalo, it encounters the Juniata coming in from 

 the northwest. Here the two rivers have formed a plain or 

 inland delta, 3 miles long by 1^ miles wide, called Duncan' s 

 island, at the south end of which is the present confluence. 



The combined waters, pressing against the north foot of 

 Peter's mountain and flowing southwestward, gradually 

 shave off its terraced slope, and then turn and flow through 

 a gap into the Cove. 



The river, flowing slantingly down and across the Cove, 

 eastward, 5 miles, turns in through a gap in the Second 

 mountain, and flows straight on to and through a gap in 

 the Blue mountain into the Cumberland valley towards Har- 

 risborg and Chesapeake bay. 



The gradients of the Xorthern Central railroad, which des- 

 cends its east bank, should give us the gradient of the Sus- 

 quehanna river approximately, the height of rail above 

 tide at Liverpool station being 396.11, and at Bridgeport 

 depot 354.57, equal to a fall of about 40 feet in about 22 

 miles, =1.82 feet per mile.* 



♦See Report of Progress, N, table 110, pages 115 and 111, pages 116, 117. 



