116 THE SAN FRANCISCO EARTHQUAKE AND FIRE. 
same way as the conduits and pipes which crossed the fault line. 
(See the maps. Pis. LVI and LVIL) Some subaqueous pipe lines 
crossing the bay seem not to have been injured. 
Two interesting earth dams are those at the San Jose Water Com- 
pany's Saratoga reservoir, which lies in a saddle in the mountains 
and is retained by an earth dam at either end. The fault runs 
directly through the reservoir, crossing both dams approximately 
at right angles. It was reported that near the east end of the north 
dam transverse cracks were formed, which extended through the 
body of the dam. There was also a longitudinal crack on top and 
some settling of the upstream half of the dam. The reservoir seems 
to have been full at the time of the earthquake, but no evidence was 
found that any water had escaped through this dam. At the south 
end of the reservoir the fault line intersected not only the dam but 
the 10-inch outlet pipe, which was broken by the earthquake. Con- 
siderable damage seems to have been done to the dam by the water 
escaping through this broken outlet pipe. Whether the dam itself 
would have been seriously injured by the earthquake but for this 
pipe can not probably be determined. 
Professors Marx and Wing also noted in the vicinity of the fault 
a number of monolithic concrete bridges, all of which were unin- 
jured; none of them, however, absolutely crossed the fault line. 
(Cf. PI. XI, A.) These observers also report that a small concrete 
reservoir, built partly in embankment and partly in excavation, was 
wrecked by the earthquake, and seem to think that such structures 
would better be built in excavation. They found that some high 
timber frames carrying water tanks, as well as similar structures sup- 
porting steel standpipes, were intact. A steel water tower at Santa 
Clara was wrecked. The engineer who designed this tower gives an 
explanation of its failure, however, in the Engineering News for 
May 10, 1906. Very probably his explanation is correct, and if so, 
there is no reason why steel towers should not be used. Doctor 
Jordan told me of one tower that he saw which had collapsed as a 
result of the earthquake, and in which the nuts on the upper ends of 
the anchor rods stripped the threads so as to allow the tower as a 
whole to be thrown over. 
( l ENERAL CONCLUSIONS. 
THE REBUILDING OF SAN FRANCISCO. 
Unless future earthquakes are very much more severe than any that 
have occurred, there is no reason why the rebuilding of San Francisco 
should not be a successful commercial enterprise. It seems highly 
improbable that there will ever be earthquakes more severe than 
that of April 18, 1906. There is no doubt that the city can be rebuilt 
