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University of California. 



[Vol. 2. 



exposed. At Clarno's Ferry the lower and middle beds are well 

 shown, and possibly the upper beds in part. About five miles 

 below the ferry lava beds rest directly upon the middle division. 

 Along the main river from Haystack Valley to the junction of 

 the North and South Forks, and from there along the North Fork 

 to Monument, it is principally the upper beds, occasionally with 

 the middle division, that are found. On the Middle Fork the upper 

 beds seem to be the only part of the section present between the 

 pre-Tertiary basement and the lava. 



At Fossil several hundred feet of the upper division appear 

 between the Clarno and the Columbia lava. At Lone Rock only 

 the Upper John Day is exposed, though the other divisions may 

 also be present. Mr. V. C. Osmont states that south of the moun- 

 tains at Logan Butte there is a great thickness of John Day beds, 

 estimated at between 3,000 and 4,000 feet, composed of the upper 

 and middle divisions, with possibly a portion of the lower one. The 

 bottom of the section is not exposed. Though the exposures 

 are not continuous, Mr. Osmont thinks that the beds are pretty 

 certainly not repeated by faulting. Aside from the exposures at 

 Logan Butte, the writer is not aware of the existence of any out- 

 crops of typical John Day south of the Blue Mountains. 



The widening of the basin of deposition indicated by greater 

 extent of the upper beds may have been only toward the north, 

 but if the southern section is, as it appears, much thicker than the 

 northern, it is only reasonable to suppose that the basin extended 

 for a considerable distance to the south beyond the farthest point 

 to which it has been traced. 



The John Day beds are usually slightly disturbed. They are 

 generally tilted five to ten degrees. From the observations made 

 by the writer, no definite system of folds - could be made out, 

 though there seem to be several which trend east and west. Fault- 

 ing is not uncommon and in some places there has been much 

 friction along the fault planes, so that the soft beds have been 

 changed into hard slate bands several inches in thickness. Both 

 the normal and reverse types of faults are represented. Toward 

 the west end of Haystack Valley a break of unknown extent 

 brings what are probably Middle John Day strata up to the level of 



