80 REPORT OF THE CALIFORNIA EARTHQUAKE COMMISSION. 
ground toward the shore, there was a movement parallel to the shore which had the 
effect of offsetting the outer end of the pier about 25 feet toward the northwest. (Plate 
57a.) The resultant of the two movements, or the actual direction of shifting of the 
mud, was westward, or a little to the north of west; and the maximum shifting in that 
direction was not less than 30 feet. Rather more than half the pier, the part nearer 
the shore, remained straight and suffered chiefly from the slanting of its supporting piles. 
This part stands on the submerged delta of a small creek, and its foundation appears 
not to have shifted. The outer part suffered most violence near the junction of the 
shifting mud with the firmer ground, being there so completely wrecked that its plat- 
form fell. The photograph and map represent it after repairs had been made. 
In the case of Bailey’s pier, which is beyond the delta, the most important telescoping, 
as shown by the slanting of piles (fig. 27), was close to the shore, and nearly the whole 
structure was transported by the shifting mud. It also sagged more than a foot just 
beyond the middle, and the attitudes of the associated piles suggest that the sag cor- 
responds to a hollow made in the surface of the mud. The pier was so badly broken as 
to require extensive repairs, and in making these repairs Mr. Bailey used the old material 
for flooring, but found that he had enough lumber remaining for 12 feet of flooring, so 
that he inferred a shortening of 12 feet. The whole pier was shifted to the northwest, 
being given a curved form (plates 57B and 58), and the maximum amount of shift- 
ing in that direction was at least 25 feet, altho the circumstances did not admit of 
accurate measurement. Combining the movement toward the shore with the offset 
parallel to the shore, it is probable that the direction and the maximum amount of 
shifting were about the same as in the case of the Martinelli pier. 
It is a notable feature of this displacement that the disturbed material moved up the 
slope instead of down, so that the transfer was not only independent of gravity but 
opposed to it. The phenomenon, therefore, does not fall in the same category with land- 
slides, and if properly interpreted it may throw light on the mechanics of the earthquake 
pulses. 
The area thru which the shifting of the mud took place is indeterminate. It affected 
a shoal parallel to the west shore of the bay and more than a mile long. At the piers 
the width of the affected region was at least 400 feet and may have been much more. 
The reported closing of the channel suggests 700 or 800 feet as a minimum estimate, but 
the outer margin of the affected area was probably beneath the water of the bay and 
outside the range of observation. The firmer part of the Papermill delta appeared not 
to be included in the movement. All of the area known to be affected lies southwest 
of the fault-trace, which in that neighborhood is about 2,000 feet from the shore. 
THE QUESTION OF LOCAL ELEVATION AND DEPRESSION OF LAND. 
Introductory. — Dr. C. Hart Merriam was told by an Indian living near Marshall, on the 
northeast shore of Tomales Bay, that since the earthquake the clam belt on that shore 
had been less accessible. The tides also came higher than formerly, the highest tides 
surrounding his cabin, whereas formerly they did not reach it. Mr. C. J. Pease, of 
Olema, also stated that the clam industry on the northeast shore of Tomales Bay had 
been much injured by changes due to the éarthquake. Thru President D. 8. Jordan I 
was put in communication with Dr. S. 8. Southworth, of Bolinas, who reported various 
phenomena indicating a lowering of the land on the east side of the fault, and a lifting 
on the west side. On September 27 and October 15, 1906, being in Bolinas and its 
vicinity, I made a preliminary examination of some of the features described by Dr. 
Southworth. They were of such a character that it seemed desirable to enlist the aid 
of zodlogists and botanists, and to this end a conference was soon afterward called in 
