Prof. Blake on the Diluvial Deposits in California, 389 
neous elevation of the whole country or in.the recession of the 
ocean. But the most important questions connected with these 
been subject to the action of any local upheaving agencies, we 
may conclude that the whole of the district through which. they 
are now seen in situ, must have formerly formed the bed of an 
ocean, the bottom of which must have been on a.level with the 
tops of the highest ridges at present existing in the country, and 
that the deep and precipitous valleys which now run between 
these ridges must have been worn out by the action of water, 
either rushing in strong currents from the interior of the country, 
or else by the disintegration and denudation of the roc 
slow process of atmospherie agencies, or as is most probable, by 
both of these processes combined. f 
As regards the direction of the currents by which these masses 
of rolled rock were brought into their present position, I have 
not been able to form any decided opinion from the character of 
the pebbles, although the metamorphic sandstones have never 
been observed in situ so low down as where these deposits are 
found, and in which they exist in considerable quantities, but on 
account of the country beyond the mining regions being inhab- 
ited by hostile Indians it was impussible to follow the traces of 
these deposits so far towards the axis of the ridge as 1 wou 
have wished. One or two facts however have presented them- 
selves which would indicate that the direction of the currents at 
the locality where these facts were noticed, was from the north- 
east.. At a short distance from Coon Hollow is a hill, the pres- 
ent surface of which is about on a level with the rock on which 
the diluvial deposits rest.. The crest of this hill is formed by a 
large vein of quartz almost vertical, and running N, W. and S.E. 
On the east side of this ledge, the slates which compose the 
body of the hill, are found rising to the surface of the ground, 
on a level with the top of the ledge. On the other or west side 
of the ledge the slate has been washed -out or at least removed, 
to the depth of about twenty-five feet and the hole thus formed 
has been filled in with the diluvial deposit, amongst which how- 
ever are found’ many masses of quartz perfectly angular, and 
which undoubtedly came from the vein. There were also layers 
of quartzose breccia mixed with these deposits. The formation 
of this eavity on the southwest side of the vein would be pro- 
duced by a current from the northeast, washing out the rock on 
