42 The Siskiyoa Island. 



one realizes the great thickness of those 

 Eocene beds, for in spite of the evidence these 

 hills furnish of long continued deep weather- 

 wearing, they present to-day a feature of 

 striking magnitude. In several places among 

 these Benton county hills Cardita planicosta 

 attest the Eocene age of these rocks. 



Another exposure of the fossils of this 

 great belt of Eocene is found near Albany. 

 A low range of hills tends eastward from a 

 point north of Con-allis, compelling the Wil- 

 lamette to run eastward for ten miles or more. 

 Near Albany this range contains our charac- 

 teristic Eocene shells in fine condition and 

 goodly numbers. This is a mere off-shoot of 

 the main belt which continues on unbroken to 

 speak of long continued uniform history. 



At Astoria the Columbia river cuts into 

 this Eocene belt and exposes another Eocene 

 fossil, the chambered shell Aturia, a beautiful 

 fossil, and important because it proves the 

 rock containing it to be Eocene. 



The magnitude of these Eocene deposits, 

 estimated in the light of what one sees along 



