1921] Lawson: The ^loiility of tlie Coast Ranges of California 449 



divergence is not great in view of our fundamental hypothesis that 

 the strain is generated by a suberustal flow, liiis flow could scarcely 

 be parallel in all its parts, and divergences in the underflow might 

 result in corresponding divergences in the strain creep in the over- 

 lying crust. The displacement gives us a rate of strain creep of 

 .045 meters per year. Applying this rate to the interval 1891-1906a 

 we find that the point must have moved .675 meters farther, to the 

 position D. The rebound, therefore, was from Z> to C, a distance of 

 1.29 meters in the direction 101°. This displacement may be resolved 

 into two components; one of .94 meters in the direction 144°, or 

 parallel to the general strike of the San Andreas fault ; and the • 

 other of .88 meters in the direction normal to the fault and away 

 from it. This last figure appears to represent the same apparent 

 transverse shift of the ground for which we found the measure to be 

 .58 meters at Tamalpais, and .57 meters at Chaparral. The consistency 

 of the results for all the five important stations thus far referred to is 

 a strong argument for the correctness of the interpretation that has 

 been put upon the data and of the underlying hypotheses upon which 

 the interpretation is based. 



Tabulation of results. — The data and their interpretation for these 

 five stations may be conveniently summarized in tabular form as 

 follows : 



stations 



Sonoma 



Ross Mt. 



Tamalpais 



Chaparral 



Farallon 





Distance from San 

 Andreas fault 



34 km. N.E. 



7 km. N.E. 



6.4 km. N.E. 



1.8 km. N.E. 



37 km. S.W. 



Strain 

 creep 



Amount 



1.24+ m. 



1.70 m. 



1.64 m. 



1.83 m. 



1.39 m. 



Interval on which 

 rate is based 



1856-1906;j 



1859-1891 



1854-1882 



1856-1891 



1860-1891 



Direction 



183° 



182° 



168° 



173° 



153° 



Rate per year 



.025+ m. 



.053 m. 



.058 m. 



.052 m. 



.045 m. 



Total to 1906a 



1,24+ m. 



2.50 m. 



3.04 m. 



2.61 m. 



2.06 m. 



Sudden 

 move- 

 ment of 

 1906 



Due to 

 slip on 

 fault 



Amount 





1.15 m. 



1.89 ra. 



2.08 ra. 



.94 m. 



Direction ... 





324° 



324° 



321° 



144° 



Appar- 

 ent 

 trans- 

 verse 

 shift 



Amount 





.35 m. 



.58 m. 



.57 m. 



.88 m. 



Direction of 

 component 

 measured ... 





54° 



54° 



51° 



54° 



Result- 

 ant 

 move» 

 ment 



Amount 



0? 



1.20 m. 



1.97 m. 



2.06 m. 



1.29 m. 



Direction ... 





340° 



341° 



337° 



281° 



