2 University of Washington Publications in Geology [Vol. 1 



exhibit marked variations in lithologic character. Faulting and sometimes fold- 

 ing are often concealed so that structural relations in many cases cannot be solved. 

 As a result of these difficulties it becomes very necessary to secure all the palaeon- 

 tological evidence possible to aid in working out the geologic history of the west- 

 ern portion of the state and to correlate this history with that of other regions 

 to the north and south along the Pacific Coast. 



During the last eight years detailed studies have been made by the writer 

 in those areas where formations of Tertiary age are exposed. The stratigraphic 

 relations have been determined wherever possible. An especial effort has been 

 put forth to make extensive collections of fossils and in every case to record exactly 

 where these collections occur within the stratigraphic sections. Among the more 

 recent collections from the lower Oligocene formations many news species occur 

 and are described in this report. A list of localities at which Tertiary fossils 

 have been collected is included as well as faunal lists of all species within the 

 Tertiary of western Washington. 



STRATIGRAPHY 



During the past fifteen years investigations on the geology and palaeontology 

 of the Tertiary formations of the Pacific Coast have been carried on with con- 

 siderable zeal. Because of the economic relationship of these deposits as well 

 as the excellent exposures in the field the major portion of this work has been 

 done in California. Up to the present time there has been lack of agreement 

 among many of the workers in the Coast Ranges of California as to how the de- 

 posits should be classified and correlated with one another. This condition gives 

 promise of settlement in the near future and presumably a standard can be devel- 

 oped which can be used as a basis for correlation up and down the Pacific Coast. 

 Until such a time has arrived it would seem undesirable to make definite correla- 

 tions between the deposits and their contained faunas in the north with those in 

 California. Suggestions as to apparent close relationships might well be recorded. 

 Bearing these conditions in mind it would appear to be a wise policy to carry on 

 detailed investigations in restricted areas and place the results upon record so 

 that at a later date they may be available for generalizations. The main purpose 

 of this paper is to bring together the results obtained up to date from studies 

 in western Washington as a basis for more detailed studies in the future. 



The Tertiary formations of western Washington consist of shales, sandstones 

 and conglomerates of marine, estuarine and brackish water origin together with 

 intercalated lavas and tuffs. These attain a total maximum aggregate thickness 

 of thirty-four thousand feet, all of which, however, is not represented at ^.ny one 

 locality. These materials were formed during the Eocene, Oligocene, lower Mio- 

 cene and upper Miocene epochs. They have been subjected to deformational move- 

 ments and in certain areas sharply folded and sometimes faulted. A considerable 

 portion of their original volume has been removed by erosion. That which re- 

 mains is for the most part deeply buried beneath deposits of glacial drift. 



