S3 Page 16

Collector: Grinnell - 1925
Location: La Grulla, 7200 ft.
Date: Oct. 2
Page Number: 2559

this noon, for a distant cattle camp. A few
steers wandered into our neighborhood, but took
fright at us and sped out of sight. The air
is warm tonight, but doubtless due to get pretty
cool by morning, as it did last night; ice this
morning on a pan of water. The diurnal
range of temperature must be very great here, as
it is uncomfortably hot in the sunshine during
the day. This daily fluctuation, accompanied by
great dryness, must have its effect on the
animal life, as it most certainly does on the
plant life -- indirectly thus, anyway, on the
animal life. The plants have noticeably
smaller or narrower leaves than their congeners
that I am familiar with in central California,
even in the interior foot-hill country.
The San Pedro Martir Mountains proper
consist of a rolling plateau, entirely granite.
More than half the surface, I should say, is
comprised in granite outcrops or at least
of boulders or heaps of boulders, weathered
out of the country rock. The soil is mostly
of coarse granite gravel, into which the
rain and snow water sinks readily. There
is little evidence of drainage -- I mean there
are few gullies and no ravines that I have
seen. There are many "dead" basins. The
arroyo Encantada(?), on which we are camped, is