DRAINAGE OF THE SANTA CLARA VALLEY 2 
The line of the Southern Pacific Railway passes over the water- 
shed referred to at Madrone station, and the elevation at that place, 
as officially published, is 345 feet.t ‘This elevation, though much 
greater than was supposed, would not alone, however, seriously inter- 
fere with Dr. Le Conte’s theory. But if we imagine the Golden Gate 
closed, it is necessary, in order to test the validity of the hypothesis, 
to know where the lowest gaps are through which the water could 
escape to the sea. If the Madrone saddle, even with an elevation 
of 345, is the lowest pass to the ocean, then of course the water 
would flow out that way. But the Coast Survey’s topographic map 
of San Francisco shows that, if the present Golden Gate were closed 
and the water compelled to find a new outlet, it would first flow over 
the divide at Colma seven miles south of the City Hall of San Fran- 
cisco; this gap has an elevation of only 190 feet above tide. North 
of San Francisco it would also flow into the sea from Richardson 
Bay near Sausalito by way of Elk Valley, which has a watershed only 
190 feet above tide-level. 
Without further inquiry into the existence of other low divides 
between the bay and the ocean, it is evident that, even if it were 
admitted that the Golden Gate be a late topographic development, the 
Sacramento drainage did not lately flow into the Bay of Monterey by 
way of the Santa Clara Valley. It is evident also that the resem- 
blance between the fish faunas of the Sacramento drainage and the 
streams flowing into Monterey Bay must be sought elsewhere. 
The accompanying map shows in a general way the present drain- 
age of the Santa Clara Valley in the vicinity of Madrone. Attention 
is directed to Coyote Creek, which emerges from the Mount Hamilton 
range opposite Madrone station and flows northwestward into the Bay 
of San Francisco. This stream, above where it emerges from the 
hills on to the plains, drains an area of 214 square miles, much more 
than any other one stream that enters the Santa Clara Valley. From 
the mouth of the gorge where this creek debouches on the plain a 
great alluvial fan spreads out toward the south and west across the 
entire width of the Santa Clara Valley, at this place a distance of 
two and a half miles. This fan forms the watershed in the valley 
trough between the Bay of San Francisco and the Pajaro River or 
t Gannett’s Dictionary of Elevation, p. 220. 
