1916] Weaver: Tertiary Faunal Horizons 5 



The following species are common to the Molopophorous lincolnensis Zone and 

 the Turritella porterensis Zone: Cardium lorenzanum (Arnold), Crenella porter- 

 ensis Weaver, Dentalium substramineum Gabb, Drillia hecoxi (Arnold), and Natica 

 washingtonensis n. sp. 



Such forms as Marcia oregonensis Conrad, Phacoides acutilineatus Conrad, 

 Thyasira bisecta (Conrad), and Thracia trapezoidea Conrad are entirely absent 

 from the Molopophorous lincolnensis Zone, although they are among the most 

 characteristic species in the Turritella porterensis Zone at Porter. The fauna as 

 a whole is distinct from the Tejon fauna below as well as the Turritella porterensis 

 Zone above. 



Turritella porterensis Zone The starta in which this zone is typically rep- 

 resented are located in Chehalis County in the region where Porter Creek joins 

 Chehalis River. Fossiliferous marine strata occur along the bluffs of Chehalis 

 River both east and west of the town of Porter. These faunas are distinctly differ- 

 ent from the underlying Molopophorous lincolnensis Zone as well as the Acila 

 gettysburgensis Zone of the Puget Sound region. The most common species oc- 

 curring in this zone are: Cardium lorenzanum (Arnold), Crenella porterensis 

 Weaver, Malletia chehalisensis Arnold, Marcia oregonensis (Conrad), Thracia tra- 

 pezoidea Conrad, Thyasira bisecta (Conrad), Phacoides acutilineatus (Conrad), 

 Drillia hecoxi (Arnold), Exilia lincolnenses n. sp., and Turritella porterensis 

 Weaver. 



Those forms which are commmon to this Zone as well as to the Molopophorous 

 lincolnensis Zone have already been mentioned. Many of the species occurring in 

 this zone are very common in the Acila gettysburgensis Zone and it is possible that 

 the extreme lower portion of the stratigraphic section exposed at the entrance to 

 the Bremerton Navy Yard may be the equivalent of the upper beds at Porter. 

 However, such species as Acila gettysburgensis Reagan, Macrocallista vespertina 

 (Conrad), Modiolus directus Dall, Panope generosa (Gould), Eudolium petrosum 

 Conrad, Turcicula washingtoniana Dall and Turritella porterensis Weaver which 

 are very characteristic of the Acilia gettysburgensis Zone are entirely absent from 

 the Turritella porterensis Zone. 



Acila gettysburgensis Zone The type section of the Acila gettysburgensis 

 Zone is to be found within the strata outcropping at the entrance to the Bremer- 

 ton Navy Yard. Excellent exposures containing marine fossils occur at the south 

 end of Bainbridge Island and also on the opposite shore to the south. The de- 

 posits consist of interbedded massive conglomerates and medium grained sandy 

 shales possessing a thickness of at least 9,000 feet. The lowermost exposed strata 

 outcrop at Orchard Point and the highest on the north shores of Blakeley Harbor. 

 Detailed stratigraphic surveys show that the conglomerates at Orchard Point are 

 below the sandstones and shales at Beans Point on Bainbridge Island and that 

 the beds at Beans Point are about two thousasd feet below the fossiliferous strata 

 at Restoration Point. The fauna occurring in the lower portion of the Bremerton 



