108 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
relatively toward the southeast. The apparent vertical displacement seems to be decep- 
tive, or rather, it appears to be due to the settling of a wedge-shaped mass on the south- 
west side of the fault. The south side of this mass was indicated by a crack about 300 
yards farther south along the road where a crack showed a drop of several inches on the 
northeast side. On the Monte Bello Ridge, a mile southeast of the Black Mountain 
triangulation station, there were a few inconspicuous cracks, without any uniformity 
of direction. Just south of the triangulation station, the cracks were more conspicuous; 
one of them was 200 feet long, and had a bearing of N. 138° W. At and about Hidden 
Villa, a small ranch in the deep valley 2 miles northwest of Black Mountain triangulation 
station, there were no cracks in the low ground, even where they were expected, as this 
is on the line of the Black Mountain fault that crosses this region from the direction of 
Portola. 
Page Mill road. — In following the Page Mill road up Corde Madera Creek from May- 
field, the first noticeable trace of the earthquake was a crack crossing the road due east 
and west, its width varying from 0.5 to 1 inch. Wagon-tracks showed a lateral displace- 
ment of 1 inch, the north side of the crack having moved west, relatively to its south side. 
This crack was traced a short distance into the fields beside the road, where it disappeared. 
Several smaller cross-cracks intersected it at intervals. There was no apparent vertical 
displacement. About 100 yards farther south were 3 smaller cracks varying from 0.25 
to 0.75 inch in width. One ran N. 53° W., and another N. 23° W. ‘The latter, being only 
8 feet from a culvert crossing under the road, appears to have been deflected by this 
from a course running more nearly east. Here again was no evidence of vertical throw. 
Going on up toward the Alpine road from this point, more and more cracks were found, 
running approximately east and west, with the exception of several north and south ones 
where the road ran closely parallel to the stream. Less than a mile from the first crack, 
groups of cracks were accompanied by small slides of dirt from the hill to the west of the 
road, and farther on from the bluff to the east of it. The cracks ran nearly parallel with 
the axis of the branch valley lying northeast and southwest. Farther up the road, large 
cracks began to appear among smaller ones running parallel. The first of these was 2.5 
inches across and ran §. 13° E., with a downthrow of 1 inch on the east side, and could be 
traced from 50 to 100 feet on either side of the road. For a mile farther up the road, the 
cracks became so numerous and complicated that it was impossible to map any individual 
ones. They intersected and ran in all directions, and were all of varying widths, the 
largest seen measuring 8 inches across. The size of this crack, however, was probably 
partly due to its position on the side of a hill. The larger cracks could be traced for 
several hundred feet. In some places crushing had taken place, and the layer of macadam 
on the road had been humped up and broken. In this same area are many small land- 
slides, some large enough to cover the road; one has occurred since the earthquake. 
Stevens Creek. — Following the road from the junction of the Castle Rock Ridge road 
with the road from Stevens Creek to Boulder Creek toward Stevens Creek, small cracks 
appeared crossing the road in a direction of N. 1° KE. Further east nearer Stevens Creek, 
the road was badly broken up by the land sliding in two directions, N. 18° W. and N. 
47° EK. All along this region cracks varying from a fraction of an inch to 2 inches in 
width, and running from N. 48° W. to due north and south, appear every 10 feet or more, 
showing a badly broken-up area. Here and there such cracks resulted in landslides from 
the bank to the road. A crack about 2 inches wide ran N. 53° W. for some distance above 
the house, at the junction with the Stevens Creek road. On the Stevens Creek road, just 
after leaving the Saratoga road, there were cracks every 20 or 30 feet, running in the 
same direction, about N. 43° W. A mile and a half northwest of the place where Stevens 
Creek turns northeast, a strip of ground 2 feet in width and about 100 yards long had been 
broken up, with a downthrow of about 6 inches on the west side. The cracks ran N. 
