ISOSEISMALS: DISTRIBUTION OF APPARENT INTENSITY. 247 
Burlingame. — Along the line of the electric railway from San Mateo northward, many 
of the poles were left out of a vertical position, most of them leaning toward the north- 
east. At the Brewer School, in the foot-hills, about due west of San Mateo, little damage 
was done. A tall, well-built tank-house remained standing, tho the roof built over it, 
a slight, flimsy structure, was turned thru an angle of approximately 30°, but remained 
on top. 
Tho there were no large brick buildings, many of the houses in the vicinity of Burlin- 
game were badly wrecked, due to the falling of extra heavy chimneys thru the roofs. 
Brick walls generally fell, unless low and especially well built. 
Millbrae. — At Millbrae there are but few buildings that could be affected by the shock, 
but the brick power-house of the San Mateo electric line was partly wrecked. The north 
and south walls fell, while the east and west ones remained standing. The latter stood 
because they were held by the steel trusses which spanned east and west. 
In the vicinity of Millbrae and San Bruno, it was found that several of the small creeks 
were well filled with débris of various kinds that had been brought down by an unusual 
flow of water following the shock, and several days after the earthquake the streams 
were still carrying a small amount of water. 
San Bruno. — Near San Bruno, where the county road crosses a small stream, there 
were numerous cracks in the ground from 3 to 10 inches wide, parallel to the line of the 
road, which is N. 25° W. The road at this place was built 8 feet above the mud flats, 
so that these cracks are accounted for by the settling of the fill. There are not many 
houses in the vicinity of San Bruno Station by which to judge of the intensity, but in the 
few houses seen the chimneys had all fallen. The race-track buildings at Tanforan, north 
of San Bruno, were not materially damaged, altho the buildings and bleachers are flimsy 
wooden structures. Plate 97c illustrates the effect of the shock upon the track of the 
electric railway on the marsh west of San Bruno. 
THE MERCED VALLEY DISTRICT. 
The Merced Valley district includes not only the valley proper, but also the area covered 
by the main body of the Merced sediments, from the San Andreas fault-line, east by 
Baden to South San Francisco and along the southwest face of the San Bruno Mountain, 
and by the cemeteries to the Life Saving Station on the coast north of Lake Merced. 
Baden. — Baden, at the south end of the Merced Valley, consists of only a few houses, 
none of which shows marked effects of the earthquake. The track of the electric tram- 
way line, just south of Baden, shows evidence of intense disturbance. (See Plate 97p.) 
The roadbed which was built up nearly all the way here was cracked parallel to the rails. 
One crack varied from 2 inches to a foot in width, and extended about 1,000 feet along 
the filled-in roadbed. For this distance the double tracks were twisted back and forth 
in a zig-zag fashion, and up and down to some extent. One rail was bent 2 feet hori- 
zontally and 10 inches vertically. Not a single rail in this 1,000 feet remained straight 
or in place, but in no case werethe rails detached from the ties. Most of the poles sup- 
porting the electric wires were thrown out of line. The ties were shoved back and forth 
and from side to side, leaving clean, bare places where they had slid about. 
The tracks of the Southern Pacific Railway line, which are parallel to the electric road 
in the vicinity of Baden Station, were slightly disturbed but not so badly that trains could 
not run over them. The Southern Pacific roadbed is much better ballasted than the 
electric line, because it is older and has become more firmly packed, which is the reason 
that it was not disturbed like that of the electric line. This disturbed portion of the 
electric line continues about 200 feet north of a road by the Baden Station, until a cut 
is reached where filling up was no longer necessary. The cracks were thus confined to 
the filled ground. 
