564 ARNOLD AND HANNIBAL— MARINE TERTIARY [April 19, 



In 191 1 the junior writer was commissioned to continue the 

 exploration at private expense and the months of June, July, and 

 August were spent in examining the various described sections and 

 districts of the Oregon coast and western Washington. With the 

 opening of the spring of 1912 as opportunity offered, short trips 

 were undertaken from Seattle to points about Puget Sound and the 

 Straits of Fuca, and three weeks were spent on the southwest coast 

 of Vancouver Isand. In June extended field work was resumed and 

 a trip made from Port Townsend west to Cape Flattery along the 

 north coast of Washington, following which two months were spent 

 in southwestern Washington. Six weeks more were given over to 

 further collecting in western Oregon, field work being concluded 

 in October. 



The present paper, preliminary to more extended accounts of 

 the stratigraphy and palaeontolog>% is based primarily on the work 

 done in 191 1 and 1912. The faunas listed here include described 

 species obtained at, or in the vicinity of, the several type sections or, 

 if the deposits are referred to formations described first from Cali- 

 fornia, characteristic faunas from some district on the North Pacific 

 Coast in lieu. 



Bedrock Complex. 



The bedrock complex on which the marine tertiary deposits were 

 laid down varies widely from place to place. 



In southern Oregon the underlying rocks are chiefly Mesozoic, 

 the Franciscan (Myrtle in part), Dothan, and Galice formations of 

 Jurassic age, and the Knoxville (Myrtle in part), Horsetown, and 

 perhaps also Chico formations which are Cretaceous (the Knoxville 

 may extend into Jurassic). These have been partially described 

 by Diller" and Londerback^° though much work still needs to be 

 done to elucidate the complicated stratigraphy. 



In the Olympic Mountains the Tertiary rests indiscriminately 



9Roseburg Folio, No. 49, U. S. Geol. Sur., 1898; Port Orford Folio, No. 

 89, U. S. Geol. Sur., 1903 ; Mesozoic Sediments of Southwestern Oregon, 

 Am. Jour. Sci., XXIII., 1907, p. 401-421 ; " Strata containing the Jurassic 

 Flora of Oregon," Bull. Geol. Sac. Am., XIX., 1908, p. 367-402. 



^^ " The Mesozoic of Southwestern Oregon," Jotir. of Geol., XIII., 1905, 

 P- 514-555- 



