44 MEXICO AND CENTRAL AMERICA 
Stratification of Remains. Atzcapotzalco was 
once an important center of the Tepanecan tribe situ- 
ated on the shores of Lake Tezcoco. It was an early 
rival of Tenochtitlan, the Aztecan 
capital, and was conquered and partly 
destroyed in 1439. The principal 
modern industry of Atzcapotzalco is 
the making of bricks, and several 
: mounds and much of the surface of 
q the plain have been removed for this 
a f purpose. In the mounds are found 
many pottery objects of the Toltecan 
period, while on the surface of the 
ground are encountered fragments of 
Fiz. 10. Atz- the typical Aztecan pottery in use 
capotzaleo Des- when the Spaniards arrived. 
a odes he tem” The stratification of the plain 
Place of the Ant. varies in different places so far as 
the thickness of the different strata is 
concerned, but the order is always the same. At one 
locality it is as shown in Fig. 11. First comes a layer of 
fine soil of voleanic ash origin, probably deposited by 
the wind. ‘This is five or six feet in thickness, yellowish 
at the top, and much darker towards the bottom, with 
streaks and discolorations. The Aztecan pottery is 
found close to the surface, while Toltecan pottery occurs 
in the middle and lower sections. Underneath the soil 
layer lies a thick stratum of water-bearing gravel mixed 
with sand. ‘This gravel stratum is possibly the old bed 
of a stream that formerly entered Lake Tezcoco near 
this point. In some places it is fifteen or eighteen 
feet in thickness. Scattered throughout the gravel are 
heavy, waterworn fragments of pots as well as more or 
less complete figurines of the archaic type. 
At other sites, such as Colhuacan, the Toltecan layer 
