210 University of California Publications in Agricultural Sciences [Vol. 1 



represent the best and most extensive of these, the object being 

 to ascertain to what depth and in what percentage the humus 

 reaches under favorable conditions. 



Fifteen valleys in nine counties north of the Santa Ynez 

 Mountains have their soils represented in the series of columns, 

 and in the accompanying tables are arranged in order of occur- 

 rence from north to south. 



AYe may conveniently follow the usual subdivision of the 

 Coast Range counties and arrange the table into the counties 

 north of San Francisco Bay, embracing seven soil columns ; the 

 hay region itself, embracing the country east and west of the bay 

 as far south as San Jose, represented by eight soil columns ; and 

 the counties south of the bay as far as Santa Barbara, represented 

 by nine soil columns. 



North of the Bay Region 



The valleys represented in this section of the Coast Range 

 are Russian River, Santa Rosa, Los Guillocos, Sonoma, Napa, 

 and Vaca : there are other important though much smaller ones 

 east and west of these and in the counties further north, from 

 which we were unable to secure columns. 



Russian River Valley. — The soil columns from this valley 

 were taken from the alluvial lands of the hop fields belonging 

 to Mr. T. Boone j\Iiller, six miles south of Healdsburg, and 

 from the red hills three miles southwest of Healdsburg, Sonoma 

 County. 



Sa)ita Rosa Valley. — The western part of the valley has a 

 heavy adobe soil, which is not so largely in cultivation as the 

 more loamy land of the eastern and middle part. A column of 

 twelve feet depth was taken from the creek alluvial on the 

 Vrooman orchard east of Santa Rosa. 



Los Guillocos Valley. — This valley is not very wide nor long, 

 and it opens northward into Santa Rosa Valley. Its soil is a 

 reddish loam and is represented by a column taken a short dis- 

 tance southeast of Kenwood, Sonoma County. 



Sonoma Valley. — The valley opens southward to San Fran- 

 cisco Bay and is largely covered by marsh lands, but the northern 



