1885.] found near the City of Mexico. 743 
ico in connection with the Lake of. Tezcoco, isolated deposits of 
this, silicified calcareous rock are seen, showing that the volcanic 
upheaval extended over a large surface, and that the thermal 
waters appeared several times. One of these deposits is to be 
found at the height of two meters above the present ground 
among rocks of the hill de? Tepeyac, north of the City ot 
Mexico. 
The geological circumstances of the event once determined, 
and notwithstanding that the paleontological data are wanting 
that might mark with precision the relative age of that deposit, 
it is to be believed that it must be of remote antiquity, consider- 
ing the circumstances which the mentioned rocks present, as well 
as the geological phenomena which have there taken place and 
of which no notice is given in the hieroglyphics or traditions of 
the ancient Mexicans. 
This consideration alone is enough to believe that the man of 
the Peñon is prehistoric The odontological characteristics indi- 
cate that this man belonged to an unmixed race, the teeth being 
set with regularity and corresponding perfectly the upper with 
the lower. They present the peculiarity besides, that the canine. 
teeth are not conical, but have the same shape as the incisors; a 
peculiarity which has been observed in other teeth found in very 
ancient graves of the Toltecs. 
The size and shape of the bones of the limbs are those corre- 
sponding to a man of ordinary stature, and from the appearance 
of the teeth the man must have been about forty years old. 
The greater part of the cranium having been destroyed, it was 
not possible to determine its diameters and thus classify it. The 
stratigraphical and lithological characteristics of the ground seem 
to indicate that the formation belongs to the upper Quaternary 
or at least to the base of the present geological age. 
It may as well be remarked that at the foot of the steep slope 
of the Tepeyac hill, near the place where the calcareous sedi- 
ments are to be seen among the rocks of the hill, as was pre- 
viously mentioned, some excavations were made, and Professor 
Don Antonio del Castillo found various bones of ‘Quaternary 
animals enveloped in a calcareous rock similar to that of the 
Pefion. The distance between this hill and the Tepeyac is nearly 
three miles. 
The excavations continue at the foot of the hill del Peñon, with 
