516 GEORGE DAVIS LOUDERBACK 



The Dillard series. 



General characteristics of the Franciscan. 



Identity with the Franciscan. 



The Whitsett limestone fossils. 



The Jurassic question. 

 Extension of the Franciscan. 

 The Shasta (Lower Cretaceous) Sea. 

 The Boundary of the Klamath Mountains. 

 Nomenclature. 

 Summary of Results. 



INTRODUCTION 



During the summer of 1904 the writer, in the course of an inves- 

 tigation of the glaucophane schists of California, made a trip into 

 southern Oregon for the purpose of comparing the geological relations 

 of the schists reported as occurring there with those of similar rocks 

 in California. In particular, the Oregon schists were said to occur 

 in a formation corresponding to the Knoxville and Horsetown of 

 California, and were considered as contact products of irruptives 

 which were intruded into the formation, and were therefore con- 

 sidered at least post-Horsetown in age. In California, on the other 

 hand, similar schists are found in the Franciscan, a thick and impor- 

 tant series of formations which underlies the Knoxville unconformably, 

 and the greater part of whose basic intrusives, if not all, are pre- 

 Knoxville in age. No schists have yet been found in the California 

 Knoxville or later rocks. It would be of considerable interest, then, 

 to the student of petrographical provinces, if such rocks, which are 

 apparently due to rather uncommon conditions, and which in the 

 United States are, so far as known, limited to this coastal (Cali- 

 fornia and Oregon) region, had been developed in different parts of 

 this territory in formations which differ both in age and in lithologic 

 characters, and in relation to igneous rocks of apparently different 

 ages of intrusion. 



The study of the field relations of the Oregon schists, however, 

 have led to the conclusion that they were developed in formations 

 of the same age and lithologic characters, and have the same asso- 

 ciations and relationships, as the corresponding schists in California. 

 At the same time, certain important features of the Mesozoic stratig- 



