534 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



Ritter 12 . Professor R. S. Holway 13 of the University of Cali- 

 fornia has published two papers upon the physiography 

 of this region and its environs, "The Russian River, a Char- 

 acteristic Stream of the California Coast Ranges," and 

 "Physiographically unfinished Entrances to San Francisco 

 Bay." What little the writer has to add to these problems is 

 but slight modification of Professor Holway's principal thesis. 



Concluding the paper upon the Russian River, Professor 

 Holway makes the following statement : "In attempting to 

 summarize the history of the Russian River in its various 

 parts the limitations noted in the introduction, namely, the 

 lack of maps showing the topography and the areal geology, 

 necessarily limits definiteness of statement in any conclusions 

 stated. In briefly recapitulating the conclusions already 

 offered in the discussion of the various sections, some com- 

 ment will be made concerning their probability or concerning 

 possible alternative hypotheses. 



The lower river is termed antecedent and is considered the 

 remnant of a former consequent coast stream which has held 

 its position despite the slow uplift. It is possible that much 

 of it flowed over the soft recent deposits and by the removal 

 of that series has been let down upon older rocks in which it 

 now flows. Technically such a history may justify the use 

 of the term "superimposed", but in no place is the present 

 river out of harmony with the minor topography in the way 

 that the Middle River is in various places. The antecedent 

 condition of the Lower River fully accounts for leaving 

 the open Santa Rosa Valley and crossing the western high- 

 land in a canyon. The Lower River is termed antecedent, as 

 a sufficient explanation. If superposition of the river upon 

 the Merced series ever existed, it has not resulted in any re- 

 lations that are not explained by its more antecedent char- 

 acter. The Middle River in its peculiar cutting off of the 

 point of a ridge in Alexander Valley, in its course through 

 Fitch Mountain, and in incising its channel on the slope of 

 Santa Rosa Valley, exhibits the characteristics of a super- 

 imposed river, — a conclusion justified by the existence within 



12 Ritter, Wm. E., Idem, p. 88. 



"Holway, R. S., Univ. Calif. Publ., Geog. Dept., vol. 1, No. 1, p. 38, 1913; Univ. 

 Calif. Publ., Geog. Dept., vol. 1, No. 3, 1914. 



