Sag Se Se ges Te ae ee ay ee ee eee ae 
A. Gray—Forest Geography and Archeology. 89 
From the Gulf of Mexico to the Gulf of St. Lawrence, the 
amount of rain decreases ae and oni regularly from 
south to north; but, as less is needed in a cold climate, there 
is enough to nourish forest. throughout. pre the Pacific coast, 
from the Gulf of California to Puget Sound, the southerly 
third has almost no rain at all; the middle portion less than 
our Atlantic least; the northern third has about our Atlantic 
average. 
Then, New England has about the same amount of rain-fall 
in winter and in summer ; Florida and Alabama about one-half 
more in the three summer than in the three winter months,—a 
fairly equable distribution. But on the Pacific coast there is 
no summer rain at all, except in the northern portion, and 
there little. And the winter rain, of forty-four inches on the 
northern border, diminishes to less than one-half before reaching 
the Bay of San Francisco; dwindles to twelve, ten, and eight 
reach the United States boundary below San Diego. 
Taking the whole year together, and confining ourselves to 
the coast, the average rain-fall for the year, from. Puget Sound 
to the border of California, is from eighty inches at the north to 
seventy at the south, i. e., seventy on the northern edge of Cali- 
fornia; thence it diminishes rapidly to thirty-six, twenty (about 
San Francisco), twelve, and at San Diego to eight inches. 
The two rainiest regions of the United States are the Pacific 
coast north of latitude forty-five, and the northeastern coast 
and borders of the Gulf of Mexico. But when one is rain: 
the other is comparatively rainless. For while this Pacific 
rainy region has only from twelve to two inches of its rain in 
the summer months, Florida, out of its forty to sixty, has 
twenty to twenty-six in summer, and only six to ten o ‘it in 
the winter months 
Again, the diminution of rain-fall as we proceed inland from 
the Atlantic and Gulf shores, 4 is ve the 9, ah that is 
so favored with winter rain is but a narrow “strip, betwee 
the ocean and the Cascade Mountains. East of the latter, the 
amount abruptly declines,—for the year from eighty inches to 
sixteen; for the winter months, from forty-four and forty to 
eight and four inches; for the summer months, from twelve and 
four to d one. ok 
So we can understand why the Cascade ae abruptly ee 
separate dense and tall forest on the west from treelessness on _ 
the east. We may conjecture, also, why ph North Pacific 
forest is so magnificent in its devolopment. : 
