THE EARTH MOVEMENT ON THE FAULT OF APRIL 18, 1906. ol 
EXTRACT FROM REPORT ON A RECONNAISSANCE OF TOMALES BAY REGION. 
By R. S. Houway. 
Below is a copy of the few notes made by me during the trip to Tomales Bay, October 
26-28, 1906. The object of the trip was to examine the shore lines of the bay for indica- 
tions of recent changes in level as shown by the effects on animal life. Drs. Kofoid and 
Torrey, the biologists of the party, recorded observations in detail and I have merely the 
general note as follows: 
“The upper limit of barnacles was found to be a quite sharply defined line on the rocky 
shores of the bay. Any recent change in level of a foot or more would have been easily 
detected in my judgment. No evidence of such change was found. sf 

REPORT ON AN EXAMINATION OF PLANTS ON PEPPER ISLAND, BOLINAS LAGOON, 
APRIL 9g, 1907. 
By Wiuus L. JEPSON. 
Salicornia ambigua Michx. Pickle-weed. — This is the most abundant species and forms 
extensive colonies on both sides of the fault-trace. The difference in color of the areas on 
the two sides of the trace at once strikes the eye, the east area being dull or dead brown, 
the area west a livelier or greenish brown. This difference in color was found to be corre- 
lated with a difference in health. The plants west of the fault are in normal condition; 
the plants east of it are either dead or dying. Dead plants still standing show wasted or 
shrunken black stems. Dying plants show shrunken main axes bearing above a few short 
joints of green which are very much thicker than the main axis. In the normal plant the 
joints are no thicker or scarcely thicker than the main axis. A broad and very marked 
zone of dead or dying Salicornia surrounds McKennan Island which lies east of the fault. 
Statice Limonium L. var. californica Gray. Sea Lavender. — Rather common in small 
areas on both sides of fault-trace. West of the fault plants are in normal condition, with 
large bright green leaves. East of the fault plants are dead or unhappy. Dead plants 
consist of nothing but caudices or short branching stems which form miniature forests 
of black stumps in the lowest places. Unhappy plants are those struggling to maintain 
existence and showing only a small tuft of small leaves. Similar colonies of dead plants 
were found on McKennan Island. 
Grindelia cuneifolia Nutt. Marsh Grindelia. — The majority of the plants east of the 
fault are dead. Many plants west of the fault are dead, especially immediately west of 
the fault. The dying out is, in the main, doubtless due to old age in the colony. 
Mesembryanthemum cequilaterale Haworth. Sea Fig. — Plants immediately west of the 
fault were healthy. One plant was found immediately east of the fault; this was killed 
completely. , | 
Distichlis spicata (L.). Salt-grass. — Plants west of fault were thriving more than plants 
east in adjacent areas. (This species ranges to 600 feet above the sea.) 
Frankenia grandifolia C. and 8. Yerba Reuma. — Similar slight differences as in the 
preceding case. 
Triglochin maritima L. Arrow-grass. — Coming up freely like young blades of grass 
west of the fault. Not appearing at all or reluctantly on east side. 
Jaumea carnosa Gray. Fleshy Jaumea. — Less readily found on the east side of the 
fault. Plants on the west side were in somewhat better condition. 
Populus species. Planted. — All individuals on east side of fault were dead. 
Summary. — The difference in the health of the plants east and west of fault-trace indi- 
cates comparatively recent changes in conditions and would be explained by the assumption 
that there had been a change of level east of the fault. If there has been no such change 
it would be difficult to say why the affected areas should conform closely to the fault-trace. 
The plants on McKennan Island were also examined. The argument in favor of assuming 
a depression for Pepper Island east of the fault would hold good for McKennan Island. 
On the other hand, I should be strongly against the opinion that the condition of shore-line 
plants indicated a change in level on the east shore of Bolinas Lagoon, 
