30 F. II. Knowlton — Jurassic Flora of Oregon. 



At the suniniit tliere are found tlie invertebrates Aacella 

 Pioclii and A. crassicoUis, but between the summit and the 

 plant bed, 1,200 feet below, only faint indications of plants 

 have been noted, though according to Mr. Diller "The plant 

 beds at the so-called Todd locality conformably underlie by a 

 few feet only a conglomerate containing indefinite vegetable 

 fragments as well as good specimens of Aucella PiochiiP 

 From the presence of shells and plants and the lithologic 

 similarity of the intervening beds to those of the Myrtle, the 

 whole is referred to this formation. 



The only Jurassic plant in any way determinable that was 

 found in the area and strata usually containing a Lower Cre- 

 taceous flora, occurred about 3 miles northeast of Riddles. 

 This was a minute fragment, which was very questiohably 

 identified as Tmniopteris oregonensis, and was found in asso- 

 ciation with Aucella Piochii. If this identification had been 

 positive, or even reasonably certain, it would be the only 

 known instance of the two floras overlapping, but it is 

 altogether too fragmentary to be taken as conclusively afford- 

 ing such evidence. 



3. Nichols Station, Douglas County, Oregon. 

 This is a small area, mainly on Cow Creek, about half a mile 

 north of Nichols Station, and is entirely surrounded by rocks 

 of Eocene age. The beds, only about 200 feet in thickness, 

 are composed of "fine, dark, shaly sandstone or sandy shale." 

 Their relations to the underlying beds cannot be observed, and 

 their reference to the Myrtle was based largely on a single 

 specimen of Aucella Piochii, which was in a loose piece of 

 matrix, not certainly found in the plant beds. As a locality 

 for the Jurassic flora, however, it is of the greatest importance, 

 no less than 45 forms having been found here. [See table on 

 pp. tt3-45.] 



Jf. Elk River, Curry County, Oregon. 



This area, which lies about 40 miles directly southwest of 

 the areas in Douglas County, is of limited extent, ranging 

 along Elk River from near the mouth of Blackberry Creek to 

 the forks of the river and up the North fork for a distance of 

 about a mile and a half ; on the South fork the plant beds 

 extend for only 200 yards. The section is about 1000 feet in 

 thickness and is made up of sandy shale, nnich veined with 

 calcite, "frequent layers of calcareous material, beds of sand- 

 stone, and fine conglomerate." 



According to Mr. Diller,'^ "These plant beds are underlain 

 on the South fork by a mass of conglomerate containing in its 



*0p. cit., p. 376. 



