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University of California. 



[Vol. i. 



feet in Strawberry Canon. These beds lie upon the upturned and 

 abraded edges of the rocks of the Shasta-Chico, Monterey, and 

 Berkeleyan series indifferently. The only exposure of the base of 

 the formation is along the southwestern limit of the Campan basin 

 from the ravine at the southeast corner of La Loma Park to Such's 

 ranch in Strawberry Canon. Along this line the formation rests 

 directly upon the surface of the sandstones of the Shasta-Chico 

 series, except for that small portion of it which lies between the 

 south and middle forks of Strawberry Creek, where a patch of 

 the Monterey chert and shale formation intervenes between the 

 Campan and the Shasta-Chico. The entire contact is one of 

 marked unconformity. No single bed of the formation can be 

 traced out continuously along the contact upon the older rocks, 

 owing to the softness of the beds and the readiness with which 

 they break" down into soil. There are, however, numerous expos- 

 ures of clay shales, thin beds of limestone, and thick beds of 

 conglomerate, and the Shasta-Chico sandstones are generally easily 

 recognizable as soon as one leaves the higher formation, so that the 

 contact is nowhere indeterminate. It is, moreover, indicated by a 

 line of change in the profile of the hills. The best exposures of the 

 limestone beds are in Wolsey Canon in the line of the creek and on 

 the summit of Serene Hill on the University Campus. The beds 

 are thin, probably not exceeding six inches in thickness. The rock 

 has the same compact texture and light-gray color which charac- 

 terize the fresh-water limestones of the Berkeleyan series. No 

 fossils have, however, as yet been found in it. The shales are most 

 abundantly exposed in Wolsey Canon, and they are well known 

 from well borings to underlie the grain field between the south and 

 middle forks of Strawberry Creek, on Such's ranch. Above the 

 basal beds the formation is chiefly conglomeratic, but beds of sand- 

 stone also occur and are well exposed in the gulch to the southeast 

 of Fog Bluff. In the upper portion of the same gulch there is an 

 exposure of some twenty or thirty feet of red clays and clay shales. 

 There are good exposures of conglomerate, part of it admixed with 

 volcanic material, in the vicinity of Such's ranch-house. For the 

 most part the conglomerate yields a soil full of water-worn pebbles, 



