F. II. Knowlton — Jurassic Flora of Oregon. 55 



brate faunas, as the writer does not feel competent to do this, 

 but simply to point out certain salient facts regarding their dis- 

 tribution and interpretation. In the first place, to mention 

 briefly the invertebrate faunas associated with the Lower Cre- 

 taceous flora of California and Oregon, it may be observed that 

 there is no conflict between the two lines of evidence. Thus, 

 near Eiddles, Oregon, as Mr. Diller says: ''Both fauna and 

 flora agree with the stratigraphy in correlating this area of the 

 ' Myrtle ' with the Shasta on the western side of the Sacra- 

 mento Valley." In the area on Redding Creek, California, 

 the shells are regarded as being of lower Horsetown age, which 

 agrees with the Shasta age of the plants, while concerning the 

 numerous localities on the western side of the Sacramento 

 Yalley, the plants and shells are again in accord with the 

 stratigraphy as regards the position and identity of the beds. 

 That they are of Lower Cretaceous age no one appears to 

 question. 



Turning now to the areas which have supplied the Jurassic 

 flora, we find that at Thompson Creek the only invertebrate 

 evidence is a fragment that may not even be a shell. At 

 Buck Peak the nearest plant horizon is 1200 feet below the 

 point at the summit where Aucella crassicollis is found, 

 though only a short distance below a conglomerate containing 

 Aucella Piochii. The only plant found in the intervening 

 beds — and this a mere fragment — occurs near Riddles, also in 

 association with shells of Aucella. Piochii. From the area 

 near Nichols Station, one of the most important of the plant 

 localities, a single example of Aucella Piochii is reported, but 

 it was not found in place and it is not known that it even 

 came from the plant beds, though possibly it did. In the 

 beds at Rattlesnake Creek, the only invertebrate evidence 

 reported is that of ''two small shells which appear to be 

 young specimens of Unio, though they may belong to some 

 marine genus instead " ; obviously they are not of importance 

 in fixing the age. 



There remain for consideration but three localities at which 

 a fauna has been found in direct and positive association with 

 the Jurassic flora. First, that at Oroville, California, where 

 the invertebrates, while not abundant or very well preserved, 

 are regarded as " more probably " belonging to the Mariposa, 

 with a suggestion of the resemblance to the older Jurassic 

 faunas of the Taylorsville region. Here again fauna, flora 

 and stratigraphy are in agreement. It finally resolves that 

 Big Bar, California, and Elk River, Oregon, are the only 

 localities at which flora and fauna are apparently not in accord. 

 The only named invertebrate found at the flrst mentioned 

 locality is Aucella crassicollis. Concerning this and the 



