THE EARTH MOVEMENT ON THE FAULT OF APRIL 18, 1906. 85 
Postscript. — Since the preceding paragraphs were written, some additional data have 
been gathered bearing on the question of the elevation of land between Bolinas and Point 
Reyes. As the most satisfactory biological evidence with reference to changes in level 
had been found in the response of the plant Salicornia, it occurred to me that pertinent 
information might be obtained by examining the lower limit of land vegetation at Liman- 
tour Bay. That bay is an extensive, ramifying, drowned valley lying east of Point Reyes 
promontory. It is separated from the ocean by a spit, past the western end of whicha 
channel is maintained by tidal currents, just as in the case of Bolinas Lagoon. The 
eastern end of the bay is at the western base of the ridge bounding the Ft 
trough, and is 8 or 10 miles northwest of the abalone eke 
If the land in this locality was raised at the time of the earthquake, the height of the 
tide at all stages, with reference to the land, would be lower; and the lower limit of Sali- 
cornia, being dependent on the relation of the land to tide water, would descend the 
slope in response to the change in level. The feature, therefore, to be lookt for was a new 
growth of Salicornia at a lower level than the older growth. Such new growth was 
actually found (June 5, 1907), not in a continuous belt, but in numerous patches hav- 
ing certain common characteristics. 
At the points visited the tide marsh characteristically ends in a little step or bluff about 
8 inches high. Above this step the gentle slope is covered by a mat of vegetation in 
healthy condition, the dominant plant near the step being Salicornia. Below the step 
is a mud surface, which usually inclines more rapidly than the platform above. If I 
understand the origin of this topography, the step has arisen from the gradual bayward 
extension of the platform, which, by reason of its vegetal covering, is enabled to arrest 
mud suspended in the water. There is also doubtless an accumulation of the roots and 
stems of the Salicornia. In places there are outlying platforms of the nature of 
islands and similarly covered by Salicornia. On the other hand, the broader platforms 
are interrupted by channels thru which the tidal waters escape, and there are also lake- 
like hollows abruptly margined by steps a few inches high. The slope below the step 
is ordinarily of bare mud, but on it are numerous patches of young Salicornia, and 
there are similar tracts in tidal channels and in some of the lake-like hollows inside the 
platform. The vertical range of this young growth is quite definite, its lower limit 
being from 13 to 16 inches below the outer edge of the platform. In some cases the 
young growth is straggling, but usually it makes a mat as close and complete as on the 
platform above, and the height is nearly as great. It is distinguished from the older 
growth chiefly by a slight difference in color. Whether such a luxuriant and dense 
growth of Salicornia could be produced in the period of 13.5 months, I am not prepared 
to say. Except for that doubt, however, the phenomena are Just such as would be 
expected to follow an elevation of the land. 
In an estuary at the edge of the bay were two fence stakes on which barnacles were set. 
At the upper limit of the barnacles, I examined a dozen individuals, finding them all alive, 
and I saw none of the adherent plates which remain after the death of the old barnacles. 
I did not learn the history of these stakes. If placed after the earthquake, the evidence 
of the barnacles would not be in point. If placed before the earthquake, the evidence 
of the barnacles, so far as it goes, is opposed to that of the new colonies of Salicornia. 
Second Postscript, added to proof sheets in November, 1907. — Early in October, 1907, 
Dr. 8S. 8S. Southworth reported that the clam patch near Bolinas had again become 
less accessible, its relation to tides being practically as before the earthquake. The 
apparent change was not associated with any precise date, but it had been suspected 
since the middle of summer. On October 17 I visited the locality, selecting a time 
when the predicted sea-level at low tide was approximately the same as on November 
25, 1906, when J had taken the photographs reproduced in plate 568 and plate 56c. 
