THE TOPOGRAPHY OF CALIFORNIA 578 
MINOR TOPOGRAPHIC FEATURES. 
Besides the general topographic features which may be seen 
from the accompanying plate, there are others too small to show, 
but nevertheless of considerable importance. 
Terraces —There are, along almost the whole length of the 
coast, benches and rounding bluffs of more or less prominence. 
Some of these terraces are only seen after close observation, 
while others form benches of considerable width. 
As shown by Lawson," these are marks of old seashores, and 
show successive elevations of the land through Quarternary 
times. 
Mesas and table-lands——TYhese are marked features of the 
coastal plain north of San Diego, and occur on the sides of river 
valleys farther to the north. This characteristic feature may be 
observed in the Salinas Valley at King City. Lawson has shown? 
that the Pliocene corresponds to a time of general subsidence 
of the coast, when the sea encroached upon the land, flooding 
the low coast lands and valleys. These flooded coast margins 
and valleys thus became the dumping ground for the sediment 
from neighboring lands until the accumulations grew to great 
thickness. Then, when the land rose and erosion carved this 
accumulated sediment, mesas and table-lands were left. 
Alluvial cones and fans.—In parts of the state where the rain- 
fall is light or not sufficient to carry the disintegrated rocks any 
considerable distance it is common to see along the valleys, at 
the mouths of mountain canyons, the valley built up higher, so 
that the mouth of the canyon is buried beneath a cone of débris. 
The writer has observed this in the White Mountains near the 
California-Nevada state line, where, standing at a commanding 
place some five or six miles from the mouth of a large canyon, 
it seemed as if all the débris removed to cut out the canyon had 
been distributed at the mouth of the canyon and extended in 
tBull. Dept. Geol. Univ. Calif., Vol. I, Nos. 1, 4 and 8. 
2 The Geology of Carmelo Bay, Bull. Dept. Geol. Univ. Cal., Vol. I, No. 1. 
The Post-Pliocene diastrophism of the Southern Coast of Calif., Bull. Dept. 
Geol. Univ. Cal., Vol. I, No. 8. 
