236 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
general public should share their interest, and uphold and enforce the provisions they 
deem it wise to make against future disasters. 
A good indication of the value of deep piling as a foundation structure was furnished 
by the conduits of the cable-car system on lower Market Street. On account of the 
constant tendency of the whole district to subside from year to year, as the filling material 
became more closely compacted, these conduits were constructed upon piling to secure 
permanence of grade. On both sides of them the street sank in places as much as 2 feet, 
and the pavement was broken, fissured, and thrown into waves. These tracks did not 
escape entirely, but for several days, before street repairs were made, they constituted 
a narrow raised path along the center of the street. 
Altho in this part of the city the fire did much to conceal the earthquake damage, a 
few little spots, especially along the water-front, where water was available, escaped its 
devastation. A building on Spear Street near Folsom, occupied by the National Bolt 
Works, illustrates what must have occurred in the case of many small brick structures. 
Its side wall was thrown down and the entire structure lurched out of plumb. To be 
sure, this building was heavily loaded on its second floor; still it was not so badly dam- 
aged as many partly standing walls in near-by districts swept by fire. The earthquake 
cracks, being sinuous, and recurring with a rude parallelism, were easy to distinguish from 
cracks opened by heat, or by the stresses induced by the wrenching away of falling walls 
or by dynamite. Buildings erected upon good foundations withstood the ordeal well, 
even when the streets around them were deprest and fissured. The Appraisers’ Build- 
ing furnishes a good illustration of this; it is substantially built of brick upon a piling 
foundation, at the corner of Washington and Sansome Streets, and still stands without 
significant damage. The levels of its foundation walls were not disturbed. (See fig. 53.) 
High intensity was developed thruout a small elongate district having a width of about 
two blocks, which extends from near the corner of Eighth and Mission Streets to the 
vicinity of Fourth and Brannan Streets; from this point the boundaries are irregular and 
very sinuous, leading to the water-front at about the crossings of Third Street with Berry 
and Channel Streets. A glance at the geological map, No. 17, shows that the regularly 
bounded portion of this district corresponds very closely with the area of a former tide- 
marsh, drained and flooded by one or two small tidal streams. The former shore line of 
Mission Bay was just north of Brannan Street, between Fourth and Fifth Streets, so that 
the irregular seaward portion of the district lies outside the old shore. 
This is one of two localities in the city, the other being a “‘made”’ land tract along 
the former course of Mission Creek, in which destructive effects of great magnitude were 
conspicuously developed. Only in very close proximity to the fault was greater violence 
manifested. For blocks the land surface, paved streets, and building plots alike, were 
thrown into wave forms, trending east and west about parallel to the length of the area. 
The amplitude and wave-length of these earth billows, and the distances to which they 
extend, are indefinite and irregular. The fissuring and slumping, and the buckling of 
block and asphalt pavements into little anticlines and synclines (arches and hollows), 
accompanied by small open cracks in the earth, characterize the land surface. This 
slumping movement or flow took place in the direction of the length of the area, and its 
amount was greatest near the center, or channel, where the street lines were shifted east- 
ward out of their former straight courses, by amounts varying from 3 to 6 feet. A 
satisfactory photograph of this phenomenon was not obtainable, owing to the quick 
convergence of parallel lines in perspective, but to the observer in the field it was a very 
striking result of the shock. 
The greater part of the district was occupied by wooden dwellings and shops, with a 
small percentage of mediocre brick buildings and a few of substantial construction. The 
fire swept the area clear. Not even heaps of débris remained to cover the ground, most 
