1913-] STRATIGRAPHY OF PACIFIC COAST OF AMERICA. 577 



says " the unpublished notes of Prof. Condon, formerly State Geol- 

 ogist, state that the backbone of the Coast Range consists of argil- 

 laceous shales, which contain invertebrate and vertebrate fossils,, 

 frequently in concretions. Some of the latter are Physoclostous 

 fishes with strongly ctenoid scales. To this formation. Dr. Condon 

 gives the name of Astoria Shales. Above this is an extensive Ter- 

 tiary deposit rich in Mollusca, which is usually interrupted by the 

 central elevations of the mountain axis. Prof. Condon refers this 

 to an Upper Miocene age under the name of the Solen beds." 



As in the instance of other Tertiary formations named before 

 the modern exact method of describing a type section or area and 

 basing a formation on it came into use, the definition of the x\storia 

 Shales is vague, and has led to the inclusion under that name of 

 nearly all the Lower Miocene-Oligocene of northwestern Oregon 

 in spite of unconfirmed suspicions on the part of several California 

 geologists that more than one horizon was represented there. Un- 

 der the circumstances it is desirable to go back and see what Con- 

 don intended the name to cover. 



At the time of Hannibal's visit in 191 1 the sequence of faunas 

 and range of species in the North Pacific Coast Oligocene and Lower 

 Miocene were not understood, and except for keeping the material 

 from the several localities at Astoria separate no attempt was made 

 to work out the stratigraphy and it was not until the excellent sec- 

 tions exposed along both coasts of the Straits of Fuca were care- 

 fully collected in during the spring and summer of 191 2 that a 

 definite clue to the presence of two formations at Astoria was ob- 

 tained. A second visit was paid to the section there during that 

 summer, and later, through the courtesy of Prof. Collier, Condon's 

 collection at the University of Oregon was briefly examined with 

 the idea of deciding what Condon intended the "Astoria Shales" 

 and " Solen beds " to include. 



From the Astoria Shales there is in the Condon collection a 

 quantity of invertebrate material and fish remains-'' largely incased 

 in gray limestone concretions, and derived without doubt from the 



26 See the forms figured in the Atlas Geol. Wilke's Expl. Exp., 1849, 

 PI. XVI.-XVII. 



