582 ARNOLD AND HANNIBAL— MARINE TERTIARY [April 19, 



Locality 51 ; basal marly tuffs, bluffs at old logdam on Porter Creek 

 one and one half miles above Porter, Washington. (H. Hannibal.) 



Locality 52; massive shaly sandstone, bluffs one fourth of a mile below 

 logdam on Porter Creek, Porter, Washington. (H. Hannibal.) 



Locality 53; massive shaly sandstone, bluff on Chehalis River below 

 Porter, Washington. (H. Hannibal.) 



Locality 54; massive shaly sandstone, bluffs along Porter Creek three 

 fourths of a mile above Porter, Washington. (H. Hannibal.) 



Locality 55; massive shaly sandstone, cut on Lytle logging R. R. near 

 top of ridge one mile above switch, Porter, Washington. (H. Hannibal.) 



Locality 56; massive shaly sandstone, bluffs along Porter Creek one mile 

 above old logdam, Porter, Washington. (H. Hannibal.) 



Locality log; basal tuffaceous conglomerate, beds immediately overlying 

 basalt at quarry on N. P. R. R., one mile west of Oakville, Washington. 

 (H. Hannibal.) 



Locality 20/ ; tuffaceous shale, bluff's along Vances Creek two and one half 

 miles above junction with Skokomish River and thirteen miles above Union 

 City, Washington. (Thos. Purdy, Ed. McCreavy, and H. Hannibal.) 



The Seattle Formation. 



In the sections at Gettysburg, Bainbridge Island, Lincoln Creek, 

 Nasel River, Nehalem River, Yaquina River, and several other 

 points the San Lorenzo formation is overlain conformably by a suc- 

 cession of beds usually finer grained, thinner bedded, and more cal- 

 careous, though the exceptions are too numerous to mention, con- 

 taining a rather different fauna of less distinctly tropical type and 

 a forerunner of the boreal Twin River fauna which succeeded it. 

 The most fossiliferous exposures of this formation are in the upper 

 beds of the northward dipping Seattle monocline extending from 

 Restoration Point on Bainbridge Island across Admiralty inlet to 

 Alki Point, Georgetown, and Columbia City in Seattle and reappear- 

 ing east of Lake Washington near the mouth of Coal Creek below 

 Newcastle. The maximum thickness is exposed on Bainbridge 

 Island and aggregates perhaps 3,000 or 4,000 feet of beds. 



Other exposures are to be found in Washington on the north 

 coast east of Gettysburg and at the mouth of the Sekiu River, in the 

 uppermost Oligocene beds of the Lincoln Creek section, the beds 

 unconformable beneath the Monterey sandstone south of Elma on 

 Delazine Creek, the lower Nasel River and Ilwaco Sections, and the 

 bluffs at Grays River. In Oregon the Astoria Section, the beds at 

 Nehalem Harbor, and those about the head of Yaquina Bay are 

 contemporaneous. 



