2X6 



- University of California. 



[Vol. 2. 



ashy mud was taking place very rapidly. The wide extent of the 

 plant beds, which seem to be present at nearly all of the well- 

 known occurrences of the formation, indicates the existence of lacus- 

 trine conditions, intermittently at least, over this region during the 

 Clarno epoch. 



The thickness of the Clarno formation is not less than 400 feet. 

 It will probably be found to exceed that limit. The strata are 

 usually gray to buff but sometimes show brilliant coloration in 

 shades of red, green, and blue. 



The relations of the Clarno to the Cretaceous may be seen just 

 east of the town of Mitchell, where a considerable thickness of 

 andesite and tuff is resting upon the Chico. Again, on the wagon 

 road between Allen's Ranch and Mitchell, the Clarno appears to 

 rest upon the western side of the Knoxville anticline. 



Where the Clarno has been found in contact with the John Da)' 

 there is no apparent angular unconformity of the strata. The dif- 

 ference in induration and weathering is, however, very noticeable. 

 The sedimentary parts of the Clarno show a much greater degree 

 of induration than the John Day beds immediately above, and tend 

 at all localities to form steep bluffs ornamented frequently with 

 balanced rocks or grotesque figures. The soft beds of the Lower 

 John Day normally weather into rounded, mud-covered domes or 

 more gently sloping banks. 



On the river above Clarno's Ferry, this formation dips about 

 1 5 to 25 to the north and beneath the Lower John Day. Fine 

 exposures continue along Pine Creek east of the Ferry. North of 

 the town of Fossil the Clarno is again seen typically developed 

 and dipping under the John Day. Along Currant Creek it is well 

 exposed and is close to, or in contact with, the Columbia lava. 



At most of the localities mentioned the Clarno shows a con- 

 siderable thickness of lava beds toward the top. These flows are 

 not, however, the uppermost part of the section. The base of 

 the formation is formed by andesite flows in several places but it 

 was not determined whether the whole section is present at these 

 points. 



At most of the Clarno localities where careful collecting has 

 been done, plant remains are found to be fairly abundant. 



