FEWKES] CASA GRANDE MOUNDS 87 
earth or clay, which has fallen from the walls, burying the founda- 
tions, augmented by sand blown by the winds. Mounds of the sec- 
ond class are composed solely of débris; when opened, some of these 
show stratification, as if formed of mud or soil deposited artificially 
on them from time to time in clearing out reservoirs or making 
other excavations, while others contain ashes and fragments of pottery 
scattered through the soil from the surface to a considerable depth. 
Certain of these mounds are devoid of features suggesting artificial 
origin. 
Mounds of the first class admit of still further classification into 
two kinds: (a) Those 
arranged in clusters, 
each resting on a plat- 
form, bounded by a 
surrounding wall— 
these are remains of 
compounds; (b) com- 
pact blocks of rooms, 
each without a sur- 
rounding wall, known 
as clan-houses. While 
the name Casa Grande 
is here applied to the 
main building of one 
compound (A), the 
designation Casa 
Grande Group of 
mounds includes all the 
clusters of adjacent 
mounds situated on 
the reservation. For 
many years the main 
building and a few 
outlying walls (fig. 12) were the only structures projecting above the 
surface, but now it is known that the historic Casa Grande is but one 
of many aboriginal buildings in this neighborhood. Excavations 
have established the fact that many mounds of the Casa Grande 
Group are remains of former houses, and that there are as many 
others composed of the débris of former habitations. 
For convenience of study and reference the large walled inclosures 
constituting the first class of mounds, called compounds, are desig- 
nated A, B,C,D,and E. These will be considered in order. 
Fic. 12. West wall of Font’s room (about 1880). 
