350 CARNEGIE INSTITUTION OF WASHINGTON. 



or Oligocene age. This flora, which is the most world-wide in distribution of 

 the three, is characterized by the abundance of a sequoia similar to the 

 living redwood (Sequoia sempervirens) . Associated with the sequoia in the 

 Bridge Creek flora are forms whose living relatives form part of the modern 

 redwood forest of California. Of these, a species of alder and of oak closely 

 related to the living red alder (Alnus rubra) and to the tanbark oak (Quercus 

 densiflora) are the most abundant. The occurrence together of this group 

 of fossil forms seems to indicate the existence in the early Tertiary of con- 

 ditions closely similar to those producing the modern redwood forest in the 

 Coast Ranges of California, It seems safe to predict that a continued study 

 of this living forest will furnish many suggestions as to the floristic nature 

 and physical requirements of the related Tertiary floras. 



Besides the conspicuous redwood element in the Bridge Creek flora, there 

 is a group of about half a dozen species representing genera no longer found 

 on the Pacific Coast, but all of which are common to-day in the moist forests 

 of the eastern United States and Europe. Their absence now in the West 

 appears to be the result of climatic restrictions imposed during the Pleistocene 

 and of mountain barriers which serve to limit migration westward. In all of 

 the work involving taxonomic and ecologic comparisons between fossil and 

 living forms, the suggestions of Dr. Frederic E. Clements and Dr. Harvey M. 

 Hall, of the Carnegie Institution of Washington, and of Dr. Willis L. Jepson, 

 of the University of California, have been of great service. 



A definite start has been made on the study of fossil wood. The United 

 States Geological Survey, through the kindness of Dr. David White, has made 

 a considerable number of thin sections from wood secured at localities fur- 

 nishing Tertiary leaves. These have been studied, in cooperation with Dr. 

 Clements, and appear to show characters which will be of diagnostic value in 

 checking the generic references made from a study of the leaves alone. 



A number of new fossil localities has been discovered through the assistance 

 of the staff and students of the Department of Geology and the Museum of 

 Palaeontology of the University of California and of the staff and students at 

 Stanford University. One of the most interesting of these has furnished what 

 appears to be a Pliocene flora from the Coast Ranges near Santa Rosa, Cali- 

 fornia. Although of small size, this flora is of particular interest since it tends 

 to fill the gap at the upper end of the Tertiary, from which few plant fossils 

 have been found. 



Hay, Oliver P., U. S. National Museum, Washington, District of Columbia. 

 Report on work done on the Pleistocene epoch and its vertebrate fossils. 

 (For previous reports see Year Books Nos. 11-21.) 



A large part of the time during some months since September 1922 was 

 occupied in proof-reading the volume on the pleistocene and its vertebrates of 

 the region east of Mississippi River. This volume was issued as publication 

 No. 322 in February 1923. All of my available time during that period and 

 since has been employed in the final preparation for the press of the volume on 

 the same subject for the middle region of North America. This is now ready 

 for publication. 



Description of the Pleistocene and its vertebrate fauna for the region west 

 of the Rocky Mountains is being prepared and is well advanced. 



