228 GUIDEBOOK OF THE WESTERN UNITED STATES. 



Lagunitas (an artificial reservoir), and beyond it ridge after ridge 

 of tlie Coast Range. To the west is the vast Pacific. 



From the summit of Tamalpais one sees clearly that San Francisco 

 Bay is a sunken area in which hilltops have become islands and penin- 

 sulas. This area is the northern extension of the crustal block whose 

 sinking formed Santa Clara Valley. A later sag admitted the ocean 

 into the valley; and the Golden Gate^ formerly a river gorge, became 



a strait. 

 Mount 



IT 



hich the Tavern of Tam 

 Feef): and West Peak fS 



peaks 



From the grassy hills 1^ 



miles west of West Peak there is a good view of Bolinas Lagoon, 

 though which passes the San Andreas rift, but for close views of the 

 rift topography the visitor should walk or drive through the valley 

 between Bolinas Lagoon and Tomales Bay, where the effects of the 

 movement of 1906 are still in many places clearly evident. 



com 



group 



though it is cliiefly sandstone. A mass 



occurs 



W 



no may be seen at sevei 

 walking: and of marine 



Muir 



woods), and back across tlie hills to Mill Valley may 



recommended 



miles. The 



Woods, which, hear the name of California's greate 



monument, presented to the nation by WiUiam Kent 



Member of Conoress from the first Califomi 



■m 



woods. 



memory of John 



WTitmgs have contributed so much to the movement 



finest scenic resources 



ownership, for pubUc enioyment. some 



The geologic event of greatest human mterest on the Pacific coast 

 in modern times was the San Francisco earthquake of 1906. It 



The earthquake ^^^ produced by a sudden movement of the rocks 



.„ (faulting) along opposite sides of a f 



acture which 



may be traced for many miles in the 



The fissure existed before the earthquake of 1906, and it is evident 

 from the relations of hills and valleys along its course that it has 

 been the scene of earher and, for the most part, prehistoric move- 

 ments. The last movement was mainly horizontal and in places 

 amounted to about 20 feet. The San Andreas rift, as this fissure 



lies 



marked 



