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University of California. 



[Vol. a. 



is a flat of even surface but a gentle slope toward the river. Its 

 outer edge is probably 1,000 feet above the stream, and hence 

 it cannot be referred to as a portion of the 850-foot terrace, but 

 it appears to be a remnant of the gentle slope which bordered 

 the alluvial plain of the 850-foot terrace period. The gentle 

 slope on the north of the river which rises back of Donahue 

 Upper Plat has an elevation and altitude very similar to this 

 flat. The latter has a length of several hundred yards trans- 

 verse to the slope, and extends back over 100 yards. 



The Owl mine, situated high in the hills on the north of the 

 river, opposite the Wilder Ferry, has been worked to the extent 

 of about a third of an acre, exposing waterworn bed-rock of black 

 slate, overlain by a comparatively fine gravel bed, very few boul- 

 ders exceeding a diameter of one foot. The local slate formation 

 is largely represented, but boulders from above the slate belt occur 

 in sufficient abundance to prove that at this point at least it is 

 an ordinary river deposit. The colors near the base are light 

 brown, yellow and gray, but higher deep red prevails. The fine, 

 soft material above has slidden into the mine and obscured the 

 section. This fine material contains a great quantity of water- 

 worn and subangular slate debris. 



At 165 feet above the exposed bed-rock the flat surface of 

 the terrace occurs. The extent of this flat was not measured, 

 but was estimated at twelve or fifteen acres. It is bordered on 

 the west by a shallow ravine, and beyond this there is a narrow 

 slate ridge rising about 150 feet higher than the terrace. On the 

 east there is an undulating tract rising somewhat higher than 

 the flat, and apparently composed of slate. The surface of the 

 flat is even, although it rises quite perceptibly toward the north, 

 but is cut off in that direction by the deep gulch of Salstrom 

 Creek. The terrace remnant appears to be the flat floor of a 

 valley about 1,000 feet wide and trending north-south. In the 

 same direction, beyond Salstrom Creek, a depression of the 

 proper size and shape to be another remnant of the bed-rock 

 floor of this valley, leads into the valley of Camp Creek, near 

 the point where Donahue Upper Plat approaches Camp Creek 

 Valley. Therefore, the Owl Plat may represent a stage of the 

 main river or of Camp Creek. The latter seems the more 



