28 Y\ REPORT OF PROGRESS. E. W. CLAYPOLE. 



valley to flow through another of an entirely different char- 

 acter. 



The easiest way to overcome the difficulty is to speak of 

 the lower Sherman's valley and the upper Sherman's valley; 

 but as the name was first given to the stream at its mouth, 

 it should be reserved for the lower valley through which it 

 flows, L e., from Shermansdale down. But then it becomes 

 very hard to find a name or names for the upper parts of 

 its course. 



Still more difficult it is for the geologist to use such terms 

 as "Juniata Valley" and ' k Susquehanna Valley," which 

 mean in ordinary language merely the farming country 

 bordering the Juniata or the Susquehanna river, whether 

 confined to narrow meadows inclosed between cliffs or ex- 

 panded into side valleys running back into the country. 



In fact, to the descriptive geologist a great river channel 

 cutting across the outcrops of a country is no valley in the 

 proper sense of the term, but merely a local accident of the 

 true valleys of the conn try, which geologically pass across it, 

 without regarding it or being influenced by it at all. 



Thus Sherman's valley, really, /. e., geologically, includes 

 Duncan's island and New Buffalo, and runs on north of 

 Peter s mountain far into Dauphin county. 



Thus also Buffalo and Little Buffalo valleys are geologi- 

 cally one and the same ; uniting in a curve around the west 

 end of the Roseburg hills, and passing on eastward across 

 the Juniata liver and across the Susquehanna river, as if 

 these had no existence, into Dauphin county beyond Liver- 

 pool and beyond Montgomery. 



Instead then of describing valleys under their pojmlar 

 or local names, the geologist is obliged to describe them 

 under the names of the soft formations along the outcrop 

 belts of which they have been eroded or excavated, and to 

 limit them by their geological boundaries, viz: The hard 

 lock outcrop ridges. 



But there is si ill another way. 



Valleys* are distinguished by geologists as of three classes 

 according t<> their internal structure, thai is monoclinal, 



♦That is such valleys as concern a report on Perry county. 



