458 



University of California . 



[Vol. 3. 



deposits had been deeply trenched by the creek, there was a 

 period when, although the stream was still large enough to move 

 boulders, there was a tendency to a filling of the valley (perhaps 

 connected with the climatic conditions of the last glacial stage), 

 but this was succeeded by the present period of active trenching. 



Opposite the upper end of the forty-foot terrace, the north 

 side of the valley contains a gently undulating tract about five 

 acres in extent, lying mostly between 50 and 100 feet above the 

 creek. Ditches show serpentine debris, and it is evidently a 

 landslide from the serpentine hills back of it. It is bordered 

 on the creek side by a steep bank of erosion. A broad, undu- 

 lating belt of similar landslide material sweeps around into the 

 valley of the Klamath River just back of the forty-foot terrace. 



The broad, even-surfaced forty-foot terrace reaches the 

 mouth of Pearch Creek Valley thirty feet below the level of the 

 terrace on which is situated the Pearch ranch, the 120-foot ter- 

 race of the Orleans Basin system. They approach each other 

 in such a way as to place this relation beyond doubt. A strip 

 of the Pearch ranch terrace several hundred feet wide 

 approaches close to Pearch Creek Canon. It is bordered by a 

 distinct slope, which leads down on to the other terrace. A 

 remnant of the latter over an acre in extent occurs in the down- 

 stream angle between the creek and the river and is bordered on 

 the river-ward side by a steep bluff sixty-five feet high, of which 

 possibly forty-five feet is bed-rock and the remainder river 

 gravel. This terrace distinctly overlooks Sandy Bar on the 

 opposite side of the river. There are no other remnants of it 

 in the immediate vicinity, but it is evidently represented by 

 the lower terrace of the Pearch Mine. 



In approaching the Klamath River, Pearch Creek descends 

 rapidly in a narrow rock canon, twenty to forty feet deep. The 

 low er strands of the Modern alluvium disappear into this canon, 

 being scarcely represented in it, but an upper strand becomes 

 a distinct terrace of creek gravel leading back a short distance 

 from the edges of the canon. Near the river this terrace reaches 

 thirty feet above the creek, and forty-five feet above the river, 

 so that it is very prominent in appearance, but when it is traced 

 up the creek it passes into the canon eroded below the "forty- 

 foot terrace" level. 



