hershey.] Tlic River Terraces of the Orleans Basin. 



455 



think there is ;tt the present time sufficient water in the ravines 

 to produce them, and it appears that no such fans have been in 

 process of formation at least since the main creek abandoned 

 the lower terrace level. 



For the first half mile below the terraces just described the 

 valley is a narrow, rocky gorge, within which there are Jin dis- 

 tinct traces of terraces. At one place the creek descends over 

 two vertical falls each twenty feet in height. Several hundred 

 feet farther downstream there is a small rock bench twenty 

 to thirty feet above the creek. 11 may or may not be related 

 to the lower terrace farther upstream. Opposite it there is a 

 great landslide deposit, which must originally have filled the 

 gorge to a depth of 300 or 400 feet, but has been trenched to 

 the bottom, an amount of erosion which seems to connect this 

 landslide, in so far as age is concerned, with the torrent fans 

 farther upstream 



At a mile and a quarter from the mouth of the creek the 

 valley widens to several hundred feet, and the floor is occupied 

 by an exceedingly irregular alluvial plain of recent age. It con- 

 sists largely of piles of boulders, being simply a series of aban- 

 doned creek beds similar to the one now occupied by the stream. 

 Small, boulder-strewn flats are developed at various levels 

 between five and fifteen feet above the creek. These Modern 

 deposits have a character which enables one to readily distin- 

 guish their correlatives higher in the valley, and there is no 

 cause for confusion of them with the terraces described above. 

 But at several points there occur remnants of a creek terrace 

 at thirty feet above the present stream, and I am inclined to 

 connect them with the lower terrace described from the valley 

 near the North Fork. 



In the angle between the South Fork and the main Pearch 

 Creek there is a deposit of loose material which I was at first 

 inclined to consider glacial in origin. It is probably about fifty 

 acres in extent. The surface is rather sharply undulating, and 

 contains a few closed basins like the "kettle holes" of a moraine. 

 At a rather fresh exposure I found rounded cobbles on which 

 were distinct scratches like glacial striae. I supposed this 

 deposit might have been formed by a glacier coming down the 



