W J<><> F\ REPORT OF PROGRE8S. E. W. CLAYPOXE. 



nected with this stream for mentioning which the present 

 is the proper place. 



All along its course and along the Buffalo valley may be 

 found scattered over the ground blocks of the white chert 

 which underlies the Oriskany sandstone and which exists 

 nowhere in the valley. It has been carried down by the ice 

 on this and other tributary streams from the south side of 

 the Buffalo hills, or rather from the north slope of Lime- 

 stone ridge to its present position. Moreover it now lies 

 30, 40, and even 50 feet above the present bed of the Little 

 Buffalo ; showing that the Little Buffalo, at least in flood 

 time, must then have flowed at that height above its pres- 

 ent level ; that it has cut down its channel and the valley 

 in which it flows to a very considerable extent since these 

 stones were deposited. We have no means at present of 

 measuring this lapse of time in years. The flint is exceed- 

 ingly hard and capable of enduring for ages, so that there is 

 no improbability in maintaining that so great an amount of 

 geological erosion has been accomplished during the life- 

 time, so to speak, of these stones. 



Mahanoy ridge. 



The second outcrop of the Hamilton sandstone in Centre 

 township forms a long, straight ridge, passing half a mile 

 south of New Bloomfield. This much resembles the Buf- 

 falo hills in structure and the description given of them is 

 applicable also to Mahanoy. It is equally steep and rugged 

 and for the most part covered with timber. Only two gaps 

 or passes exist through the ridge in Centre township, one 

 near New Bloomfield and the other about a mile farther 

 east. Through the first passes the Bloomfield branch of 

 the little Juniata, which brings down all the water from the 

 eastern part of the township between Limestone ridge and 

 Mahanoy. It is only a small brook and there isnoobvions 

 geological cause for its having chosen this spot for cutting 

 through th«' Hamilton ridge. The softness of the Oriskany 

 sandstone ^<»ut li of Bloomfield probably allowed its passage 

 throngh that barrier, and a less height of the ridge may 

 have compelled it here to cross the other. This gap pos- 



