302 JANOS TO CORRELITOS, 
The mud is filled with coarse gravel from the plateau, 
which gives greater hardness to the material. In this 
respect I consider it superior to the modern adobe, 
which is oftener made without any gravel or straw, 
although in the better class of buildings, I have seen 
both used. 
In the town of El Paso there are some old division 
walls from three to four feet high, connected with the 
earliest buildings in the place, that are built of large 
blocks of adobe, well filled with gravel, of a similar 
character with those in the ‘‘ Casas Grandes ;” but in no 
buildings of the Mexicans have I seen them used. I 
have also seen modern fences made in the same man- 
ner of the common mud taken from the fields. 
All adobe walls, whether of buildings or mere fences, 
decay first at their base, from the moisture; which 
causes them to fall over. Such is the case with the 
modern as well as the ancient buildings. When pros- 
trate, the water easily permeates them ; ina few years 
they crumble in pieces, and are reduced to the original 
mud and gravel from which they were made. 
The outer walls of the Casas Grandes are only to 
be traced by long lines of rounded heaps parallel to, 
or at right angles with, the walls now standing; while 
here and there a corner of the original wall may be 
seen, or where it was intersected by a transverse wall 
which tended to support.the other and bind them to- 
gether. These corners often retain their erect posi- 
tions long after the other portions have fallen. So 
with the higher and more massive walls of the interior, 
which are five feet in thickness at their base: the sides 
or longer walls have fallen, while the corners, with a 
