350 



SCIENCE 



[N. S. Vol. XXX. No. 767 



Synopsis of Quaternary History of California. 



and the forests consist almost entirely of 

 conifers. 



During the period of elevation the Channel 

 Islands off the coast of southern California 

 were connected with the mainland, allowing 

 mammoths to make their way across on dry 

 land. The channel was then a gulf, not un- 

 like the present Gulf of California, and may 

 appropriately be called the Santa Barbara 

 Gulf. 



After the Glacial Epoch had passed, there 

 came another era of subsidence, but this time 

 on a small scale, affecting only the immediate 

 shore-line, which stood for a time from three 

 to seven hundred feet lower than now. Dur- 

 ing this period were accumulated the marine 

 San Pedro beds, known chiefly in the Santa 

 Barbara Gulf. At first the water was a little 

 colder than at present, allowing marine life 

 now characteristic of Puget Sound to flourish 

 as far south as San Pedro. Then it became 



warmer, and, for a short time, species that to- 

 day can not live north of Lower California 

 made the Santa Barbara Gulf their home. 

 This history is remarkably like that of New 

 England, where a warm Champlain epoch of 

 depression followed the Ice Age. 



After the San Pedro epoch there came on 

 the west coast . a renewed elevation, causing 

 the streams to terrace the alluvial ' deposits 

 that had filled the lowered valleys in the pre- 

 ceding epoch. This, too, has its counterpart 

 in the Terrace epoch of New England. This 

 time has left us no marine record, but only 

 terraces on the streams, and along the shore. 



The last phase in the physical history of the 

 west coast is the recent subsidence that al- 

 lowed the sea to encroach on the river valleys, 

 forming the Bay of San Francisco, and other 

 bays along the coast. This has been going on 

 almost into modern time, for Indian shell 

 mounds, apparently made by the same race 



