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University of California Publications in Geology |VoU-7 
both of which oceur at present along the Mexican border within 
fifteen degrees of the latitude of Los Angeles. 
The collection of wading birds from the coast, while not rich 
in point of numbers, embraces a goodly variety. Jabiru, Myc- 
teria, Ciconia, Grus, Ardea, and Phoenicopterus are represented ; 
yet there is no record of the spoonbill (Ajaia) or of the ibis 
(Guara), both of which have been taken in the flesh well to 
the northward of Rancho La Brea. 
Grouse, quail, and meleagrines have been taken in various 
of the deposits under discussion; yet we find there none of the 
eracid birds such as Ortalis which occurs at present along the 
Rio Grande valley of Texas. 
The absence of the above-mentioned species, particularly the 
Raptores, from all the bird-bearing deposits thus far known to 
North America becomes very striking in view of the large num- 
ber of instances recorded of the southward retraction of species 
and genera since the Pleistocene period. It is possible that the 
forms mentioned above were more sensitive to the cold and were 
driven southward before the deposition of the Pleistocene strata 
thus far explored, or that they were, on the other hand, more 
tropical species that have only in Recent time diffused north- 
ward to their present range. Gyparchus is reported from the 
Pleistocene caves of Brazil by Winge (op. cit.) which fact would 
support the latter hypothesis. Polyborus cheriway would fall 
in the same category with Gyparchus, being represented in the 
asphalt by its close relative Polyborus tharus. The same is per- 
haps true of the Recent species of Geococcyx found in the Son- 
oran zone of California at the present time but represented in 
the asphalt only by a longer-shanked form which can searcely be 
considered as the direct ancestor of the living Geococcysx cali- 
fornianus. The species from the asphalt may be identical with 
one of the species of Neomorpha from South America, comparison 
between them having been thus far impossible. e 
Approximately eighty species of true columbine birds inhabit 
the Americas today and many of the species are forms which 
feed on the ground and which congregate about water holes 
to drink; yet there is no specimen in all the material examined 
which is referable to this group. The commonest species in the 
