EARLIER TERTIARY (EOCENE AND OLIGOCENE). 773 



Where the Clamo has been found in contact with the John Day there is no apparent angular 

 unconformity of the strata. The difference in induration and weathering is, however, very 

 noticeable. The sedimentary parts of the Clamo show a much greater degree of induration 

 than the John Day beds immediately above and tend at all localities to form steep bluffs orna- 

 mented 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 Clamo's Ferry this formation dips about 15° 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 Clamo 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 considerable 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 plamo localities where careful collecting has been done, plant remains are 

 found to be fairly abundant. Repeated attempts have been made to obtain vertebrate or 

 invertebrate fossils also, but, so far as the writer is aware, none have ever been discovered. 

 The plants are, perhaps, most common in a bed of tuff and ash, 100 or more feet in thickness, 

 belonging to the middle or the lower part of the formation. 



Knowlton ^^°^ reported on the fossil plants as foUows : 



In attempting to work out the bearing of the plants above enumerated on the question 

 of the age of the beds, it should not be overlooked that any conclusions drawn might be quite 

 different from what they would be were the whole flora of each of the localities to be considered. 

 For example. Dr. Merriam's coUection from Bridge Creek embraces only 14 previously named 

 species, whereas the complete known flora of this locahty includes over 40 species. And further, 

 it is impossible at the present time, without having worked out the affinities of the Tertiary 

 floras of Cahfornia and elsewhere, to give with any degree of completeness the outside relation- 

 ships of the flora of the John Day region. The following conclusions, however, are not likely 

 to be greatly modifled by subsequent work. 



The oldest horizon represented by these coUections seems to be that near the crossing of 

 Cherry Creek. The species, though few in number, seem to have their greatest affinities with 

 forms from the lower Tertiary, and it is probable that this horizon should be referred to the 

 lower or middle Eocene. There are a few species in common with Bridge Creek, but in general 

 its flora has a slightly older facies. 



The Bridge Creek, as already suggested, has an ample flora which is represented by a 

 wealth of individuals. A large proportion of its species are endemic, but on considering the 

 obvious relations of these, as well as the forms known from other localities, an upper Eocene 

 age is indicated. 



Several other of the localities seem to be of the same age as the Bridge Creek beds, namely, 

 li miles east of Clamo's Ferry, 3 mfles above Clamo's Ferry, and one-half mile northeast of 

 Fossil. Not more than three previously named species are known from either of these localities, 

 and not rarely the identification of some of these is more or less doubtful, but as nearly as can 

 be made out they should be of the same age as Bridge Creek. 



It win be noticed that the determination of the plant remains, both as regards the flora as 

 a whole and with respect to its subdivisons, agrees with the statement relating to stratigraphic 

 succession. The Bridge Creek beds, with the few specimens from the shales 1^ miles east of 

 Clarno' s Ferry, are considered upper Eocene, while those from Cheny Creek are held to be an 

 earlier facies. 



