Anderson.] 



Point Reyes Peninsula. 



145 



granitic surface along which the faulting has progressed. The 

 general appearance is that of a normal fault, and there is some 

 specific evidence pointing in this direction. The withdrawal 

 of the Franciscan terrane lying to the east has left detachments of 

 those rocks in somewhat elevated positions upon the flanks of the 

 granite. Similar remnants of Miocene rocks along the western 

 side of the valley opposite Olema also present evidence to the 

 same effect, yet the long succession of oscillatory movements that 

 have affected this region, and of which the present displacements 

 are a partial result, makes it difficult to make accurate statements 

 except of the most general kind. The faulting is evidently 

 complicated as one would expect as a result of complicated move- 

 ments. If there is supposed a downward enlargement of the 

 granitic batholite, then clearly normal faulting has been the most 

 pronounced, as is shown by the rocks lying along the flanks 

 of the granite. 



The small body of foraminiferal limestone upon the eastern 

 slope of Whittenberg Hill is thought to belong to a low horizon 

 of the Franciscan series, wholly concealed by depression upon the 

 eastern margin of the valley. That there has been, on the other 

 hand, enormous lateral pressure at times, and perhaps accom- 

 panying some of the oscillations, seems evident from the general 

 sheared and broken character of the granite in all parts of the 

 peninsula. This is particularly apparent in the zone of crushed 

 granite lying west of Olema. Lateral compression also seems 

 to offer the best explanation of the synclinal deformation of the 

 Miocene series in the central part of the peninsula between the 

 areas of granite. But if the downward peripheral enlargement 

 of the granite in subterranean levels be supposed, lateral compres- 

 sion could not result in normal faulting, but would produce 

 an overthrust and a consequent depression of the granitic block 

 instead of an elevation. And if the time element in the complexity 

 be considered it may well be supposed that this has been among 

 the phenomena that have taken place. It might, therefore, seem 

 that the successive elevations and depressions of the orographic 

 block, that are to be hereafter described, have had their causes 

 partially in successive compressions and stretchings of the coastal 

 crust. 



