SOIL FORMATION. 133 
twisted, and thrown down (PI. X, B) ; fissures were opened in the 
earth (Pis. Ill, IV) ; trees were uprooted and thrown to the groin id. 
or snapped off, leaving their stumps in a standing position, or split 
from the ground up through the stock to the branches (PL II). 
Roads were ruined for long distances, bridges were thrown off their 
abutments (PL XI, A), and water pipes were twisted, telescoped, 
collapsed, or broken (Pis. IX; X, A). Along the seashore immense 
landslides occurred, throwing vast quantities of earth and rock into 
the sea. (See also PL VIII, B.) 
The main pipe lines of the Spring Valley Water Company, which 
were depended on exclusively to supply the city of San Francisco 
with water, as well as the distribution s}^stem of this company in 
the city, were broken in many places, and the supply of water was 
absolutely cut off for a number of days after the earthquake (map 
PL LVI). The great mains leading from Pilarcitos, San Andreas, 
and Crystal Springs lakes were all badly broken (PL LVII). The 
Pilarcitos conduit in particular, which ran almost along the fault 
trace, was completely ruined and rendered unfit for repair (PL IX). 
The great 44-inch water main crossing the San Bruno marsh was 
thrown down from its supporting trestles in a serpentine line, and 
broken in several places. 
As the distance from the fault trace increased, the violence of the 
disturbance in a general way diminished, but this statement must 
be modified by saying that in cities and towns built upon the alluvial 
soil of valleys the destruction was at its greatest, as, for instance, at 
Santa Rosa, about 20 miles east of the fault trace, in the Sonoma 
Valley (Pis. XIV, B; XVII, A). This city, built upon a deep, 
alluvial soil, w T as more severely shaken and suffered greater damage, 
in proportion to its size, than any other town in the State. Scarcely 
a brick or stone building in the town was left standing, and 80 
people were killed. 
SOIL FORMATION. 
The destruction wrought by the earthquake amounted to little or 
nothing in well-built structures resting upon solid rock. and. all 
other things being equal, increased in proportion to the depth and 
incoherent quality of the foundation soil. Thus dwellings in Ber- 
keley, upon the solid rock, were scarcely disturbed, while those on 
the level plain of Oakland, 4 miles distant, were severely shaken and 
injured, as, also, were the buildings at Leland Stanford Junior Uni- 
versity (Pis. XIV, .1,' XV: XVI; XVII. 11: XVIII), 7 miles dis- 
tant from the fault trace: at San Jose (Pis. XII. B; XIII, //), 13 
miles distant; and at Agnew (PL XIIT, A), 12 miles distant. The 
town of Salinas and the alluvial valley of Salinas River were also 
severely shaken. This region was fissured and disturbed more than 
any other district in the State. 
7171— Bull. 324—07 10 
