1912] Miller: Pacific Coast Avian Palaeontology 83 
less than two hundred feet above its level. The locality is today 
a typical open valley country, protected on the north by the 
east-and-west Santa Monica Range, yet tempered by the cool 
and moisture-laden breeze from the sea. Faunally, the locality 
lies in the Upper Sonoran zone of the San Diego region. 
The Shasta caves oceupy a position further inland and seven 
degrees to the northward of Rancho La Brea. Their elevations 
vary between 1300 and 1500 feet above sea-level. The isothermie 
zone represented is slightly above that of Rancho La Brea, it 
being Upper Sonoran and lower Transition. The isohumie area 
is that of the Sacramento-San Joaquin, which is an area of 
slightly greater precipitation than is the San Diegan. 
The two localities are at present distinguishable in their avi- 
fauna by the presence or the absence of several species which 
are of interest in the light of palaeontological records. The 
entire group of grouse, represented in the Shasta region by 
Dendragapus, is wanting at Rancho La Brea. Oreortyx and 
Cyanocitta, present in the eave region, are wanting in the im- 
mediate vicinity of the asphalt beds. Geococcyx, present in the 
latter loeality, is wanting in the former. 
These, however, are birds of slight volant power. The species 
of less restricted activity, such as the Raptores and the water- 
birds, are common to the two localities at present. 
The Fossil Lake region of Oregon lies in latitude 43° N, full 
nine degrees north of Rancho La Brea, and is on the eastern 
side of the Cascade Range. This separation from the coastal 
slope would influence the smaller species of birds more than the 
larger. Winter temperatures would be more severe, with sum- 
mer temperatures fully equal to those of southern California. 
The rainfall at the present time is such as to give the region 
the name of ‘‘Oregon Desert.’’ 
There appears, then, as distinguishing the five more import- 
ant localities today, a difference of nine degrees of latitude, a 
range of elevation from 100 to 1500 feet above the sea, and a 
faunal difference limited to the Upper Sonoran and _ lower 
Transition zones. There is no evidence of marked change in 
elevation since Pleistocene times; hence it seems probable that, 
a somewhat similar relationship between the localities prevailed 
