THE MOUNTAIN REGION OF CLEAR LAKE. 11 
lie for the most part in a northerly and southerly direction. 
To the north and to the south of the lake are clusters of 
mountain peaks situated in the main ridges and in the trans- 
verse ridges which join them. The group to the north 
includes Mt. Sanhedrim, Mt. Hull, Snow Mountain, 
Big Horse Mountain and Elk Mountain, all lying 
about the headwaters of the south fork of the Eel River, 
which empties into the Pacific Ocean, and of minor streams 
which finally flow over the plains of the Sacramento to the 
river of that name. Again, to the south of the lake are a 
number of other peaks more scattered. The nearest is Uncle 
Sam Mountain, of volcanic formation, the next is Mt. Hannah, 
while Pluton Peak, Geyser Peak, Mt. St. Helena and others 
are much further south. These groups of peaks, especially 
in their summer vegetation, possess exceptional interest. 
Some of the plants, as has been indicated, are peculiar to 
this region, while others of wide distribution or common 
occurence elsewhere are to be found only in limited areas or 
in peculiar soils or situations. So that each mountain 
plateau, each “chaparral” ridge, each valley or each marsh 
displays in its vegetation certain distinctive floral aspects 
or characteristics which may be only in part due to purely 
local plants. 
The dividing line between the counties of Napa and Lake 
follows the ridge beyond the Knoxville mines. This is a 
vantage point of observation. Just to the east is the abrupt 
western wall of the inmost Coast Range ridge bounding the 
valley of the Sacramento. That is a dividing line of local 
importance in plant distribution in the Coast Range. The 
eastern slope of the ridge is more gradual, and the vegetation 
of the yellow foothills at its base is affected by the character- 
istics of the Sacramento Valley. From the various turns in 
the grade of the wagon-road, one may see stretching away to 
the south and southwest, a series of purple-hued ridges 
terminated on the horizon by the huge shoulders of Mt. 
St. Helena, the great landmark of all this country. That 
mountain is the headquarters of a local plant district, the 
