70 



University of California Publications in Geology [Vol.11 



Kitsap County, Washington." 52 A list of forty-four invertebrates 

 is given from three localities. 



The latest and most complete discussion of the marine Tertiary 

 of Washington by Weaver is found in his paper, "The Tertiary for- 

 mations of western Washington." 53 Detailed descriptions, which 

 were lacking in his former papers, of the stratigraphy, lithology and 

 distribution of the different formations, together with the maps, cross- 

 sections and beautiful illustrations, make the paper a valuable contri- 

 bution to the geologic literature of the state of Washington. That 

 portion of the paper dealing with the Oligocene of Washington, except 

 for the descriptions of the lithology and stratigraphy, is essentially 

 the same as that found in the last three papers by the same author 

 which have just been reviewed. The following extract, 54 taken from 

 this paper, is of general interest, as it gives Weaver's idea as to the 

 palaeogeography of western Washington during Oligocene time. 



The Olympic Mountains and Vancouver Island were probably land areas. 

 The Olympics were at least 1000 feet lower in elevation than at present, as marine 

 deposits occur at that elevation where the wagon road from Clallam Bay to 

 Forks crosses the main divide. Presumably the region had been partly reduced 

 to a peneptlain during the Cretaceous and Eocene and during the Oligocene the 

 Strait of Juan de Fuca was depressed, allowing marine sediments to form upon 

 the submerged borders of the peneplain. 



There are insufficient exposures to the Oligocene sediments to determine 

 definitely the successive extent of the seas or embayments during the epoch. 

 Sediments containing the Acila gettysburgensis zone are much more widely 

 distributed and are much thicker than those of the two lower zones. Apparently 

 there was a partial withdrawal of the seas at the close of the Eocene and new 

 invasion at the opening of the Oligocene. The embayments in which the Lincoln 

 and Porter horizons were deposited were restricted in area and possibly did not 

 cover the Puget Sound Basin area. During the upper Oligocene the larger part 

 of western Washington west of the foothills of the Cascades was covered with 

 the waters of the ocean. There may possibly have been a lowland area connect- 

 ing the Cascades with the Olympics in Pierce and southern Kitsap counties. This 

 problem is still unsolved. 



At the close of the Oligocene there was an emergence over a large portion 

 of western Washington and all of Puget Sound Basin became a land area. Em- 

 bayments were still in existence in the Strait of Juan de Fuca region as well as 

 in southwestern Washington. 



In a recent paper by Dickerson a very well-preserved fauna of ' 

 fifty species, collected by F. M. Anderson and Bruce Martin from 

 the lower Oligocene on the Cowlitz River, southwestern Washington, 

 is listed and thirty-six new species described. The fauna is referred 



52 Weaver, C. E., Proc. Calif. Acad. Sci., ser. 4, vol. 6, no. 3, pp. 41-52, 1916. 



53 Weaver, C. E., Wash. Geol. Surv., Bull. 13, pp. 1-327, 1916. 



54 Weaver, C. E., op. cit., p. 185. 



