62 University of California Publications in Geology (Vou.7 
INTRODUCTION 
When the vertebrate palaeontologist turns his attention to 
the group Aves as represented in North America, especially if 
he be confronted with the problems represented by a considerable 
mass of unassorted material, he cannot but feel that he pushes 
out into almost uncharted waters, a wide sea where the few 
islands recorded by previous explorers—islands too often 
shrouded in mist—may perhaps never appear upon his horizon. 
The scarcity of previous record, the wide separation in place of 
the bird-bearing deposits, coupled with the inadequacy of descrip- 
tions and the poverty of museums in collections of Recent avian 
osteology—all these are factors which conspire to give the student 
entering upon such an undertaking the feeling that he stands 
or falls unto himself. In full cognizance of these conditions the 
present paper is undertaken. Its dual purpose is the recording 
of certain facts but recently made known in this interesting field, 
and the correlating, insofar as this is possible, of the results thus 
far attained. E 
ACKNOWLEDGMENTS 
Study of the University of California collections was taken 
up at the invitation of Professor John C. Merriam, head of 
the Department of Palaeontology of that institution, and to his 
unstinted aid, encouragement, and advice much of what value 
this study may possess is here freely ascribed. Grateful acknowl- 
edgement is also made to Messrs. Joseph Grinnell and H. S. 
Swarth of the California Museum of Vertebrate Zoology for 
information cheerfully furnished on many Recent species and 
for the loan of osteological material. Specimens of great interest 
and value were loaned of donated by Dr. F. A. Lucas, Dr. A. 
Smith-Woodward, Dr. F. C. Clark, Dr. C. O. Esterly, Mr. E. J. 
Fischer, and Mr. J. Z. Gilbert. The very generous attitude taken 
by Madam Ida Hanecock-Ross and the associated owners of 
Rancho La Brea in issuing permits to excavate the asphalt de- 
posits made possible the assembling of much valuable material 
essential to the work. Through the personal efforts of Dr. J. C. 
Hawver, of Auburn, California, as well as by the very cordial 
