F, H. Knowlton — Jurassic Flora of Oregon. 37 



lower part many large pebbles of the greenstone like that on 

 which the conglomerate rests at the base of the 'Myrtle.' 

 No plants were found in the basal conglomerate, though it 

 contained many examples of Aucella crassicollisP On this 

 evidence the entire section was regarded as referable to the 

 Myrtle formation. 



Since the above quotation was published, in fact during the 

 past summer (1909), Mr. Diller has visited and i-e-exarained 

 the Elk liiver region of the Port Orford quadrangle, and made 

 the following important observations which he has kindly per- 

 mitted me to make use of. The plant beds — that is, the beds 

 containing the "Jurassic flora of Oregon" — he now finds to 

 be over 1,200 feet in thickness ; they rest eomformably on a 

 conglomerate which he regards as the basal member of the 

 Myrtle (Knoxville). This conglomerate contains "multitudes" 

 of Aucella cransicollis in the upper portion, while Aucella 

 Piocliii occurs, though somewhat rare, near the bottom. This 

 conglomerate rests unconformably on a mass of greenstone, 

 Avhich has supplied the pebbles in its basal portion. This 

 greenstone mass, in turn, has cut the underlying crushed and 

 quartz-veined slates and sandstones of tlie Dothan ? which 

 latter contains locally, as identified by Doctor Stanton, Aucella 

 Piocliii and Aucella Erringtoni in association. This distribu- 

 tion of the several species of Aucella in this section is very 

 significant, and will be referred to on a later page. 



The Elk River area has furnished two considerable collec- 

 tions of fossil plants which together aggregate 20 species [see 

 table on pp. 43-45]. As this entire flora, with the exception of 

 the unnamed specie of Hausmannia, is identical with that 

 found in Douglas County, it may be considered as settled that 

 the two areas are of the same age. 



This is also the first of the areas thus far considered in whicb 

 an identifiable invertebrate fauna is found in direct association 

 with the plants. The following list of names is given by 

 Doctor Stanton :* 



Spondylus? sp. 

 Aucella crass icoUis Keyserling 

 Inoeeranms ovatus Stanton 

 Turbo morganensis Stanton 

 Olcostephanus miitahilis Stanton 

 Perisphinctes f sp. 

 Iloplites Hyatti Stanton 

 JBeleninites tehamoensis Stanton 

 Helenndtes impressus Gabb 

 Pinna. 



*In Diller, Geol. Soc. Am., Bull., vol. xix, p. 378, 1908. 



