354 TRANS. OF THE ACAD. OF SCIENCE. 
to be everywhere in close contact with the limestone. At 
all. the:4 ints war ppaniei they were found to be com 
co ar 
ous rocks, with eee seams of sand and pipe ss 
These were often found focucly cemented with calcareous 
matter, and rege along the river valley a thickness of about 
three hundred fee 
The valley of ie Rio Grande varies from a couple of hun- 
dred yards to several miles in width, ane is everywhere 
Sorbet with luxuriant vegetation. Soil deep and dak 
