mouths. All of the prehistoric material described below 
came from these small caves. 
PRESENT VEGETATION 
A description of the present vegetation of the area 
will serve as a basis for comparison with the material to 
be described from the deposit. Near Bat Cave, the plains 
consist of a large playa supporting a sparse growth of 
four-winged salt bush (Atriplex canescens (Pursh) Nutt. ), 
with areas of Heliotropium curassavicum LL. and Sporo- 
bolus airoides (‘Torr.) Torr. The transition zone from the 
plain to the fossil lake terraces is marked by Russian 
thistle (Salsola pestifer A. Nels.). On the terraces Boute- 
loua hirsuta Lag. forms a thicker ground cover than is 
present on the plains. Numerous plants of the groundsel 
(Senecio longilobus Benth.), stickseed (Lappula Redow- 
sku (Hornem.) Greene), stickleaf (Mentzelia pumila 
(Nutt.) Torr. & Gray), paintbrush (Castilleja minor A. 
Gray), mock pennyroyal (Zedeoma Drummondi Benth. ) 
and verbena (Verbena ciliata Benth.) show that this area 
is relatively free of alkali. In the rocky areas of the ter- 
races a shrubby vegetation is present. M’allugia paradoxa 
(D. Don) Endl. (Apache plume) is very common, while 
Rhus trilobata Nutt. ex Torr. & Gray, Forstiera, Ly- 
cium and Ribes spp. comprise the rest of the shrub flora 
near Bat Cave. 
The arroyos and canyons nearby are better watered 
(although none have permanent streams) and conse- 
quently the herbaceous vegetation is more varied. Nu- 
merous members of the Compositae, Boraginaceae, Lab- 
tatae, Leguminosae and other families were collected. 
In no case, however, was there any extensive ground 
cover formed by these plants. 
At an elevation of 200 to 400 feet above the level of 
the plains a distinct change in the vegetation is seen. 
[ 158 ] 
