PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 
issued | 
SMITHSONIAN INSTITUTION 
U. S. NATIONAL MUSEUM 
Vol. 92 Washington : 1942 No. 3155 
THE LATE CENOZOIC VERTEBRATE FAUNAS FROM THE 
SAN PEDRO VALLEY, ARIZ. 
By C. Lewis Gazin 
Tue cottections of fossil vertebrate remains in the United States 
National Museum from deposits in the San Pedro Valley of south- 
eastern Arizona have come to be of much significance in including 
materials representing appreciable portions of previously little- 
known microfaunas of upper Pliocene and early Pleistocene stages. 
The study of these materials, for the most part collected by J. W. 
Gidley, was undertaken by him but never completed. Important 
parts of the two principal collections were left undescribed, so that our 
knowledge of the faunas as a whole was dependent upon a somewhat 
inaccurate list, compiled before portions had been studied and before 
some portions were prepared. Hence, it has been found advisable to 
complete the undertaking by including in the present paper brief dis- 
cussions of the elements of both the described and undescribed por- 
tions. Revision has been made of certain identifications and conclu- 
sions, where such changes are indicated by more recent information. 
I wish to express my gratitude to the staff of the Division of Mam- 
mals of the United States National Museum, for permitting me 
unrestrained access to the collections of Recent mammals, and to C. 
W. Hibbard, of the University of Kansas, for information pertaining 
to materials from the upper Pliocene of Kansas and for the privilege 
of examining carnivore and rodent materials therefrom. The draw- 
ings depicting Canis edwardit, new species, Spilogale pedroensis, new 
species, and Z’anupolama cf. longurio were made by Sydney Prentice. 
The others, except for a camera lucida drawing of Sylvilagus? ben- 
sonensis, new species, were made by Rudolf Weber. 
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