352 CARNEGIE INSTITUTION OF WASHINGTON. 



in the John Day basin with its wide variety and extended geological range of 

 floras. The exact position of the floras in the stratigraphic sequence, character 

 of the formations in which fossils are embedded, nature of climatic con- 

 ditions under which plants lived, examination of the wide variety of species 

 represented, and the significance of the collection as a whole in terms of climate 

 and environmental conditions have all required special attention. 



Dr. Chaney's recent study on the Bridge Creek flora of the John Day region, 

 heretofore assumed to be of Miocene age, has given us for the first time a 

 careful statistical statement of the species present. Of 20,000 specimens 

 obtained in the most recent collections, 45 per cent are alder, 14 per cent 

 sequoia, 10 per cent oak, and 10 per cent laurel (Umbellularia) . There were 

 found to be slight differences in the percentages of the common species from 

 the several levels from which specimens were secured, but in general the 

 representation of plant life is essentially the same through this section. The 

 flora as a whole has a strikingly close resemblance to that of a redwood forest 

 region of the present day on the West Coast. 



Studies of the extraordinary asphalt faunas of the Pleistocene at Rancho 

 La Brea in Los Angeles and at McKittrick on the western border of the great 

 valley of California have advanced rapidly during the year and several papers 

 have already been approved for publication. These include the monograph 

 on the sloths by Chester Stock, a study of the fossil bears of the genus 

 Arctotherium from western North America by J. C. Merriam and Chester 

 Stock, and a number of shorter papers. Two other monographs will be sub- 

 mitted for publication in the early part of the coming year. 



The monographic studies of the fauna at Rancho La Brea covering cats, 

 camels, and horses will be published as early as it is possible to secure complete 

 illustrative material. 



Excavations in the asphalt deposit near McKittrick have been continued 

 and much additional material secured. The recent collections, representing 

 both mammals and birds, are being prepared for study under the super- 

 vision of E. L. Furlong with assistance furnished by the Museum of Palaeon- 

 tology of the University of California. 



Dr. Stock in cooperation with Mr. Furlong has also been engaged in studies 

 of Pleistocene and Pliocene faunas from several localities in Cahfornia, Oregon, 

 and Nevada, these investigations being closely related to special studies at 

 Rancho La Brea and McKittrick. 



In an investigation of the geological history of the birds of America, L. 

 H. Miller, of the Southern Branch of the University of California, has con- 

 tinued his important work conducted in cooperation with and through the 

 courtesy of the Los Angeles Museum. His monograph on fossil birds of 

 Rancho La Brea has been accepted for publication along with a paper of 

 extraordinary interest on a bird fauna secured in the Miocene diatomaceous 

 deposits of Lompoc, California. 



As an end result of Dr. Miller's studies, the Los Angeles Museum has this 

 year placed on exhibition a nearly complete assembled skeleton of the great 

 carnivorous flying bird, Teratornis, found only in the asphalt beds of Los 

 Angeles and in the similar beds of slightly different age at McKittrick, 

 California. The assembling and mounting during the year 1923 of this skele- 

 ton by the Los Angeles Museum represent an important advance in our 

 knowledge of extinct life of America. 



