48 MESOZOK' FLORAS OF LMIFD STATES. 



THE JURASSIC FLORA OF DOUGLAS COUNTY, OREG 



Bv Wii.i.i.vM M. Fontaine. 



The plants descri])0(l in this paper wei'e obtained from strata that 

 occur in Douglas County, Oreg.. on or in the vicinity of Buck Mountain. 

 Some fossils were originally discovered Ijy Mr. Aui'elius Todd, in 1872, at 

 a localit>' about 300 feet l^elow the summit of Buck Mountain, which has 

 subsequently been named Todds Gulch. Since that time additional 

 collections have been made both at that locality and at others discovered 

 since.the original find of Mr. Todd. The new localities occur north of the 

 mountain on its slopes, and south of it in the vicinity of Nichols station. 



Professor Ward has given an account of the discovery of the different 

 localities, and also of the stratigraphical investigations made by Mr. 

 Diller and Mr. Brown, at the time that the last and largest collections 

 were made by himself, aided by Mr. Storrs. This account will be foimd 

 in the first paper." 



From the facts given in that paper and in a letter from Professor 

 Wanl, and also from a few notes kindly furnished l)y Mr. Diller, the 

 details that follow, regarding the position of the plant localities and their 

 geological relations to one another, are obtained. The study of the geolog- 

 ical relations of the strata containing the plants was carried far enough 

 to show that, from the most northern to the most southern localities 

 showing plants, they are continuous and form one group. At remote 

 points, however, the exact stratigraphic relations of the plant-bearing 

 beds were not made out, so that it can not be stated whether or not they 

 are the same. 



Buck Mountain is about 8 miles due west of the town of Riddles. It 

 is about 3,500 feet above sea level, and rises 2,000 feet above the streams 

 that flow along its base. On its west side, flowing north, is Olalla Creek. 

 A ])i'anch of this creek flows westward along the northern base of the 

 mountain, and is locally called Thompson Creek, but on the Land Office 

 map it is named Hunter Creek. The plant-bearing strata are exposed on 

 Thompson Creek, and at several spots collections were made from them. 

 The strata on the creek tlip toward the west at an angle of from 35° to 40°, 

 and have a strike of N. 15° to 20° E. In passing south, however, into 



"TweiUictli Ann. Kcp. U. S. Geol. Survey, Pt. II, ISHK), pp. ;«iS-;57 



