THE EARTH MOVEMENT ON THE FAULT OF APRIL 18, 1906. 109 
43° W. From here northwest the disturbance continues in the same general direction. 
A number of breaks often occurred together, arranged as steps, in each case the down- 
throw being on the east side and measuring about 4 inches, the direction varying from 
N. 33° W. to N. 3° W. Following the Stevens Creek road on down toward Congress 
Springs, several landslides were noted, mostly small ones due to caving in of the banks 
of the creek. Just west of the springs the road was badly broken, twisted, and shoved 
up in places, the downthrow being first on one side and then on the other. In some places 
along the bank the west side projected 2 inches farther than the other, while the fence 
showed an offset of 2 feet. The large stone bridge across the creek appeared intact, 
but west of it a large patch of ground had slipt down 2 feet. 
South of Congress Springs. — Near and northwest of the reservoir 2.5 miles southeast 
of Congress Springs, fissures from 4 to 6 feet wide ran nearly north and south, and past 
thru the earthen dam at the northwest end of the reservoir. (Plate 644.) The intake 
pipes at the south end of the reservoir were disconnected, and the escaping water under- 
mined a part of the southern dam of the reservoir. This reservoir is in a topographic 
saddle and has dams at both ends. The fault-trace passes thru this saddle. Where 
the bottom of the reservoir was exposed by the escape of the water, cracks of the fault- 
trace were exposed in the mud. Fences crossing the fissures showed but little displace- 
ment; the displacement moved the northeast side toward the southeast, relatively. 
The hills southeast of the reservoir have steep slopes of from 20 to 50 degrees. The 
cracks follow the east-facing slopes and the east side of these cracks had raised about 
6 or 8 inches. Southeast of the reservoir the chimneys and water-tanks were down. 
CONGRESS SPRINGS TO SAN JUAN. 
Mr. G. A. Waring, under the direction of Prof. J. C. Branner, studied the displacement 
along the fault from the vicinity of Congress Springs to its southern end near San Juan. 
The following is an account of the phenomena observed by him: 
Cracks and displacements along the fault-trace (G. A. Waring). — Starting at the upper 
reservoir about 2 miles south of Congress Springs, the fault-trace was followed to its 
southern end near San Juan. From the upper reservoir, thru which the fault past, 
cracking the dams at each end, a fairly continuous series of cracks a few inches wide runs 
down the southwest side of Lyndon Creek about 2 miles to Mr. Edwards’ place, “ Glen- 
dora.” Thruout this distance the individual cracks run S. 3° to 13° E., while the line 
as a whole trends S. 33° E. The relative movement of the northeast side of the fault is 
from 14 to 20 inches southeast. From Glendora the fractured zone becomes wider and 
not so distinct. The lower reservoir is slightly cracked and several fissures appear near 
it, but the main line of fracture seems to be nearly 0.5 mile west of it, showing in two or 
three cultivated fields. The whole ridge west of the reservoirs was severely shaken, 
however, for cracks 4 or 5 inches wide opened near Grizzly Rock and several large slides 
occurred in its neighborhood. One water-pipe running north and south on the Beatty 
place was broken, while one trending east and west was unhurt. No cracks were found 
crossing the ridge between Grizzly Rock and White Rock. The cracks were next found 
on the road about a mile east of B. M. 2135 of the U. S. Geological Survey, but they do 
not show in the vineyard to the southeast. On the ridge road, about 5 miles northwest 
of Wright Station, the fault again shows slightly in a few 2-inch cracks bearing S. 3° E., 
with a slight relative movement of the east side toward the north. Going down the 
slope from here to Wright, the cracks rapidly become larger. 
At Patchin, 3 miles west of Wright Station, there are fissures over a foot wide trending 
mainly in the direct line of the fault (S. 33° E.). Several stretches of numerous small 
