Strata containing the Jurassic flora of Oregon
Introduction PROBLEM AND CONCLUSION Two fossil floras have been reported from the Mesozoic rocks of California and Oregon, the one Cretaceous and the other Jurassic. With the former the fauna is Cretaceous, but with the latter the fauna has been regarded as a matter of doubt. It is the purpose of this paper to remove the doubt by showing that in part of Oregon and California the Jurassic flora, as illustrated in the accompanying diagram, is in the “Myrtle” and Knoxville beds, while elsewhere it extends down to the horizon of the Mariposa, and the general conclusion is reached that for the Pacific coast the line between the Cretaceous and the Jurassic is the great unconformity at the base of the Knoxville. HISTORICAL DEVELOPMENT The discovery of fossil plants by Aurelius Todd in Douglas county, Oregon, more than thirty years ago has led finally, through the collections of Will Q. . . .