252 University of California Publications in Geology [Vol.12 



In spite of the good work of Dr. Knowlton and others, the problems 

 of West Coast palaeobotany are at the present day in a stage much 

 further from final claritj' than those in other phases of palaeontological 

 investigation. A nearly continuous procession of expeditions from 

 universities and from various government organizations has spent 

 years of work in collecting vertebrates and invertebrates for the pur- 

 pose of increasing our series to such a point that we may better 

 understand the biological and time classification of the groups con- 

 cerned, but our study of the history of plants has been based almost 

 entirely upon more or less incidental collecting in field operations 

 carried on for purposes other than palaeobotanical research, and 

 covers an exceedingly short period compared with that given to study 

 of other groups. 



CONCLUSIONS 



The relative isolation of the field for palaeontological study on the 

 western side of the continent has tended to distinguish to some extent 

 the problems of this area from those of the lands to the east. Separ- 

 ated as the Pacific Coast is from other regions by high mountains and 

 wide oceans, it is natural that its isolated investigators should tend 

 to separate their special researches rather widely from those of other 

 workers. It is also clear that in past periods tlie life of this province 

 has in its evolution tended to take on provincial characters dififer- 

 entiating it to some extent from that of other parts of the world. It 

 is, however, true that the study of every group leads finally to a point 

 at which we find ourselves forced to relate our local problems to the 

 great world questions of life historj^ 



In certain aspects the history of life on the Pacific Coast is im- 

 perfectly recorded. In other pliases the information is available, but 

 is as yet only partially examined. For a considerable portion of the 

 earlier story of life we have only a meager record compared with that 

 of the Atlantic Coast. Our history of plants is largely that of the 

 later periods. Of the age of amphibians we have no amphibian record. 

 Of the wonderful world history of the great reptile group, we know 

 but a limited portion of the story of two divisions. In the history of 

 mammals we lack entirely the long record of Eocene time. After 

 subtraction of the factors which are poorly represented there is, how- 

 ever, enough remaining to give us a most extraordinary history com- 

 pared with that of most portions of the earth's crust. Progress in our 



