ately the heavy rains have transformed the roof of the cave into a set 
Las Vigas 
June 
City of 
Mexico 
(Mexico) 
December 
of trickling streams of water and the bats had gone to drier quarters. 
The walls and exposed stones on the bottom of this cave are smooth 
with a coating of gray silica dissolved above and transferred thus by 
the trickling water small stalactites and stalagmites 1 or 2 inches long 
were numerous, 
Yifoile at this locality I was surprised to get a Geoeocoyx californlac.is 
and in its stomach was the following curious assortment of foods 1 18 inch 
Butania; 4 6 inch Butania s 2 5 inch lizards ( Sceloporus ); 3 horned toads 
from 2-|- to 3 inches long; 4 grasshoppers, and several beetles. 
I reached here at 10{30 a,m. today from Washington via Chicago and 
Laredo, The vicinity of Laredo is a sandy and dry desert lying in the 
Lower Sonoran Zone. Leaving there at dark, I saw none of the inter¬ 
vening region until daybreak the next morning when we were on the table¬ 
land just northeast of Saltillo, This place is on a dry, treeless plain 
within the Lower Sonoran Zone, but about at its upper border. Just south 
H ' I ~ * ' | 
of Saltillo, at Carneros, the R.R. passes between some hills which afford 
'ir 7 _ i * 1 * v-‘ 1 • 
one a chance at the Upper Sonoran while the plains of the village are 
treeless Lower Sonoran, 
South of Carneros the road passes through the hills and descends on 
another broad open plain (treeless and with much Larrhea mex. ). Mount¬ 
ains lying to the east and west in low barren ranges like those about 
City of San Luis Potosi, Just north of Vanegas (San Luis Potosi) on west 
•4 
side of R.R, is one of tho largest prairie dog villages I have seen. It 
I ; 
must be nearly 3 miles across and contains an enormous number of holes. 
The day I passed was oool and no M dogs ,! were seen. Hear Charcas, on this 
line, the Larrhea disappeared and many large Opuntias, tree Yuccas, and 
Schinus molle come in and the country shows evidence of having a much 
- 193 
