Nov., 1910.J An Open V alky near Harrishurg, 0. 



211 



The southern part of the valley has a considerable stream, 

 which in its lower course has cut deeply into the valley floor; 

 leaving the old stream level as terraces above the present bed. 

 The terraces at their down stream end are twenty-five to fifty feet 

 above the present stream level but run out up stream. Similar 

 terraces occur along the Big Darby, but in a number of instances 

 the topographer in making the map has overlooked them, leaving 

 them either on a level with the till plain; or, as in the case where 

 this stream comes out to the Darby on the level with the flood 

 plain. 



Contour itJetval ^Ofat. 



When one first enters this through valley he is struck by its 

 size in proportion to the size of the present streams in it. Three 

 facts lead him to believe that the present streams could not have 

 carved the valley. First, these little streams would have needed 



