iSgs-l 553 [Crawford. 
to a depth of 25 feet from tlie surface of the creek, and ai'e found 
in nearly connected deposits for a distance of about 4 miles north- 
west to the margin of the Estera Real. The depth of these der 
posits beneath the present surface of the earth is not known, but 
it is believed to exceed 200 feet. Then- deposition has evidently 
continued through more than one of the epochs of the Pleisto- 
cene period, because some fragments of travertine moulds of 
leaves, etc., similar to those found near these sjjrings, have been 
found in a ravine several miles north of Estera Real, in clastic 
deposits that were interstratified with ejectamenta, and have 
been exposed at de[)ths of over 200 feet from the present surface 
of the earth. The interstratification referred to is beneath sev- 
eral others, and is associated with geological evidences of having 
been deposited in the early part of the Pleistocene. The iissure 
from which these springs, which are called Ojo de Agua, issue 
must incline downwards at an angle of 40° in order to avoid in its 
extension to the cavern beneath Obraje the deep Lake Lagunita 
which is between the springs and Obraje. 
Six miles northeast of the Ojo de Agua springs and about (> 
miles from the north foot of Obraje, is another group of large 
springs whose waters are charged with CaCog, and which also de- 
posit large quantities of travertine, and whose tufaceous encrus- 
tations, travertine substitutions, and deposits of onyx are similar 
to the depositions froni the waters of Ojo de Agua. The deposits 
from these two groups of springs commingle in an area of about 
16 square miles; their waters have the same temperature, 80° C, 
and are most i)robably from the same source and pass through 
the same strata. Both creeks discharge into Estera Real, about 
four miles north of the springs. Large quantities of diatoma- 
ceous ooze and algae are found near the springs and in the 
creeks. A noticeable effect of these waters on the soil saturated 
by them is the favorable condition produced for the vigorous 
growth of some varieties of lactiferous trees of the fig family, 
especially of matapalas, a species of Ficus, a tree with many inter- 
t^vining and inosculating aerial roots that descend from 20 
to 40 feet from the large branches to the earth where they 
develop subterranean roots. The aerial roots often grow to over 
12 inches in diameter, and, as does also the main body of the tree, 
yield by tapping a good quaUty of elastic rubber (caoutchouc). 
