Alluvial Soils. 33 
Santa Barbara at least. As a rule, these seashore lands are very 
productive, but fruits for them must be chosen with reference to 
their low level and exposure to coast influences. 
The light loams of the so-called desert region of southern 
California are not inferior in productive capacity to some of the 
best soils of the great valley, which it greatly resembles, save in 
the scarcity of humus, or vegetable matter. Only a detailed 
survey, however, can determine the tracts having an arable soil, 
as against those overrun by arid sand. The soil of the Colorado 
River bottom is highly productive, easily worked, being quite 
light. It is a highly calcareous soil, and is likely, whenever the 
water of the Colorado River shall be made available for irriga- 
tion, to yield rich returns for cultivation. 
The valleys of the seaward slope of the Coast Range have 
mostly gray, light, and silty, rather than sandy soils, quite sim- 
ilar in appearance from Ventura to Humboldt County, though 
differing considerably in composition, those of the southern 
region being more calcareous, and apparently richer in phos- 
phoric acid; as the coast region consists for the most part of low 
ranges with intervening valleys, the valleys are, as a rule, small, 
though a few show considerable area. In such a country the 
soil surface shows wide diversity within smaller areas than on 
the vast stretches of the great interior valley; consequently, so 
far as soil goes, the coast farms are often suited to a wider range 
of fruits than the interior valley farms of similar size. 
ALLUVIAL OR SEDIMENTARY LOAMS. 
These soils have been considered from the earliest plantings 
by Americans as par excellence the fruit soils of the great valley 
of central and northern California. They occur along the 
courses of existing streams, and extend back to variable dis- 
tances, until they merge into the valley loams, or adobes. These 
deposits are considerably higher than the present beds of the 
streams, and are sometimes described as “next to river bottom.” 
They consist of fine alluvium, with seldom any admixture of 
coarse materials. These river soils are usually very deep, and 
they are naturally well drained. 
These deposits cross the valley in somewhat irregular 
courses; they are of greater or less width according to the drain- 
age area whence they have come. They vary also in depth, 
and taper down on either side to the level of the red loam or 
adobe upon which they have been deposited. Such strips are 
first chosen by the fruit planters of the district in which they 
occur. In the valleys of the rivers crossing the eastern side of 
the San Joaquin Valley, there are, bordering the streams as 
well as Tulare Lake, considerable areas of brown to blackish 
