104 University of California Publications in Geology (VoL-7 
The fauna is certainly a rich one and embraces a considerable 
variety of ungulates of large size which were dependent on a 
goodly supply of grass and browse. Purely local conditions of 
dainage may, however, have brought about such a condition. In 
the fickle streams of the southwest such change of bed may occur 
in a single season and a deposit laid down under conditions of 
abundant moisture amounting almost to a peat formation may 
be left high and dry after a severe freshet to suffer a reversion 
to almost desert condition. Relatively few of the anserines are 
found in the collections from the asphalt. Geese of the Recent 
species become almost upland forms during the rainy season 
when grass is abundant. Hurenwra is, according to Hudson’s 
account in Naturalist in La Plata, a plains-dwelling form of the 
open pampa at some times of the year. The sand-hill crane, 
Grus canadensis, is notably a plains feeder in the winter and 
spring, while the great blue heron, Ardea herodias, has been 
seen by the author on the dry hillsides in midsummer seemingly 
in pursuit of grasshoppers. The presence of these birds in the 
asphalt in the limited numbers found is not then a_ positive 
indication of open water or of even marshy ground. The water- 
worn fragments of wood and the leaves in bedded deposit are 
such as occur in small steams of the region today when the 
streams may be more or less intermittant. A rich and varied 
mammalian fauna is taken by some writers as an indication of 
mild climatie conditions. Such conelusion seems scarcely war- 
ranted, however, in view of the present conditions in the desert 
parts of the world. The writer found deer abundant on the 
open and thorny desert of Lower California in the region of 
Cape San Lueas. On the mainland of Mexico, in the desert of 
Sonora, deer, peccary, and mountain sheep are abundant. The 
accounts by Roosevelt of game distribution in Africa indicate 
an abundance and a great variety of game in almost desert 
regions of that continent. On the Mohave, the Colorado, and 
the great Nevada deserts, the most ephemeral pools of water, 
even when highly impregnated with alkaline salts, are the resort 
of multitudes of waterfowl, while Cope and Shufeldt describe 
abundant lfe in the region near Fossil Lake on the Oregon 
Desert. 
