94 WARREN DUPRE SMITH AND EARL L. PACKARD 



flows and diabase. Probable equivalents of the upper portion of 

 this series are found in the lone lacustrine deposits within the Rogue 

 River valley. 



The Eocene beds have been thrown into gentle folds, which 

 even along the crest of the Coast Range are nowhere as steep as 

 those developed in the Myrtle or older beds. In places normal 

 faults have developed, the thrust fault being less frequently 

 seen. 



Eocene invertebrates occur at a number of localities. These 

 are typical Tejon forms, including the well-known Turritella 

 uvasana Gabb and V enericardia planicosta merriami Dickerson. 

 The large fauna from the Little River, Roseburg Quadrangle, as 

 shown by Dickerson, belongs to the Siphonalia sutterenses zone of 

 upper Tejon. Since this was found some 10,000 feet from the base 

 of the Umpqua-Arago series, and since the Arago of Diller has been 

 by several considered later than the Umpqua formation, it may 

 prove to be the brackish water equivalent of the lone Eocene of 

 California. 



With the beginning of the Eocene eastern Oregon became a 

 province, distinct both geologically and physiographically. The 

 oldest Tertiary beds have been described as the Clarno by Merriam,^ 

 and named after the type locality, Clarno Ferry^ Wheeler County. 

 The formation was also recognized in the vicinity of Fossil and 

 along the west side of John Day River, and was later extended 

 eastward to Heppner,^ as a strip ten to fifteen miles wide. 



The Clarno is typically composed of varicolored sandstones and 

 shales, which are in places carboniferous, grading upward into paper 

 shales and coarse rhyolitic tuffs. In places near the bottom ande- 

 sitic flows are found, while rhyolites occur nearer the top of the 

 section. 



These beds range from 400 to 2,000 feet in thickness. They 

 have dips as high as 25 degrees, which may be locally increased 

 upon fault blocks. The^ Clarno rests unconformably upon Chico 

 Cretaceous at Mitchell and upon the Knoxville ( ?) shales farther 

 west. An angular unconformity with the overlying John Day beds 



^ J. C. Merriam, op. cit., II, 285. 



^ W. G. Mendenhall, U.S. Geol. Siirv., Bull. 341, p. 406. 



