574 ARNOLD AND HANNIBAL— MARINE TERTIARY [April 19, 



recognized by European geologists, but no equivalent strata were 

 known on the Pacific Coast. In 1898 DalP^ used the term Oligo- 

 cene for the first time in connection with Pacific Coast stratigraphy 

 to cover the " Aturia bed," Astoria shales, and doubtfully (and cor- 

 rectly so since it is not a homogenous formation) the Tunnel Point 

 beds of the Oregon Coast. Following this the senior writer-^ placed 

 the San Lorenzo formation of California in the Oligocene on the 

 basis of its equivalence to strata referred to that period on the north 

 Pacific Coast. 



Were the Pacific Coast Tertiary the standard for the world it 

 is obvious that a three-fold division would be recognized. The low- 

 est member would consist of the Martinez and Tejon, equivalent 

 to the present Eocene. The succeeding division would embrace the 

 Sooke, Astoria, Vaqueros, and Monterey and correspond to what 

 has been commonly called Oligocene and Lower Miocene. The 

 third would include the numerous usually local formations of which 

 the Empire is the oldest and the Elk River and Deadman Island or 

 Santa Barbara Pliocene the youngest, in other words the middle 

 and upper Miocene and Pliocene, there being no well-marked hiatus 

 in this part of the world between beds of Miocene and Pliocene age, 

 as these divisions are currently recognized. 



A direct correlation between the Pacific Coast marine Tertiary 

 and the deposits of Europe and bordering the Gulf of Mexico is 

 impossible owing to the almost total absence of identical species 

 except in the Eocene. The nummulites and corals which have been 

 depended upon to establish the contemporaneity of the Oligocene 

 of Europe and the Antilles are not known on the Pacific Coast, and 

 there do not appear to be any other forms that will serve the pur- 

 pose. However an assumption that approximately the same time 

 interval is represented by the Pacific Coast deposits may be based 

 on certain broad resemblances. 



In the closely allied succession of strata commencing with the 

 Sooke and terminating with the Monterey, the oldest beds lack so 



22 " A Table of North American Tertiary Horizons Correlated with One 

 Another and Those of Western Europe with Annotations," i8th Ann. Kept. 

 U. S. Geol. Sur. (II.), 1898, p. 323-348. 



23 Prof. Pap. 47, U. S. Geol. Sur., 1906, p. 15 fif. 



