Stratiyraphti at Slate's Spr/)n/s. — Fairbanls. 355 
by shearing ulong the contact, a condition due to an upward 
movement of the basement rocks forming the axes of the 
mountains. Lava flows and intrusives are abundant in the 
older rocks and. with the exception of the serpentine, are ab- 
sent from the Knoxville. 
Mount Diablo. 
Turner* lias well described the metamorphic rocks of mount 
Diablo, but does not state the relation of the Knoxville to 
them. Neither does he express a definite opinion of the rela- 
tive ages of the Knoxville and diabase which is so extensively 
developed on the northwest of the metamorphic area. 
OnBagley creek the wn-iter has noted the Knoxville in direct 
contact with a gabbro-like rock, but there has been so much 
shearing that the relation is not clear, although it is evident 
that the shales near the contact are not metamorphosed. 
On the northeast side of the mountain the Knoxville beds 
are in contact with the " metamorphic rocks" (Golden Gate 
series), but the exposures are not good. As in other parts of 
the Coast ranges, the Knoxville shows a regular and even 
bedding, and dips away at varying angles from the core of 
older rocks. The soft strata of the former result in smooth, 
rounded slopes, while, in sharp contrast, rise the hard and 
more or less silicified sandstones, jaspers and eruptives of the 
Golden Gate series. 
An examination of the large diabase "massif" has con- 
vinced the writer that it is older than the Knoxville, which 
lies on three sides of it. Although the two could not be found 
in actual contact, because of the clayey nature of the Knox- 
ville, the latter appears at no point to show the slightest 
alteration due to contact with an eruptive mass. In Mitchell 
canon the shales are traced to wnthin 200 feet of the contact, 
and it is certain that if the diabase were really intrusive the 
metamorphisra would have resulted in rocks weathering less 
readily. An additional fact reported by Turner is that the 
diabase contains inclusions of the' metamorphic rocks, indi- 
cating its intrusion into them, while inclusions of the Knox- 
ville are absent. 
There can be no question that on mount Diablo we have the 
Golden Gate series with associated eruptives antedating the 
*Bull. Geol. Soc. Am., vol. ir, p. 385. 
