Boas, Franz. Race, Language and Culture – T52

[Culture]

Archaeological Investigations in the
Valley of Mexico by the International
School, 1911-12 1

During the season of 1911-12, when I had charge of the International
School of American Ethnology and Archaeology in Mexico
City, we gave much attention to the question of the sequence of
ancient cultures in the valley. Some years ago Mr. William Niven had
called attention to the wealth of material to be found in the brickyards
of Atzcapotzalco, and Professor Seler proved by investigation that comparatively
few objects belonging to the Aztec culture were found there,
while the majority were of the type of Teotihuacan. He had also noticed
a number of very curious types which were found in gravels at Atzcapotzalco
and had evidently been rolled in river beds.

To ascertain the relative age of these archaeological deposits, I entrusted
an excavation in one of the brickyards to Sr. M. Gamio, a Fellow
of the School. I also made a somewhat extended reconnaissance in the
Sierra de Guadalupe to see whether the Teotihuacan type would be
found there, either in surface layers or at a greater depth. I wish to
express here my thanks to M. Jorge Engerrand for giving us most valuable
aid in the geological interpretation of the strata investigated.

The part of the valley of Mexico in which our researches were made
lies between the Sierra de Sta. Cruz and that of Guadalupe. The bottom
of the valley rises gradually northward from the Lake of Texcoco. At
San Miguel Amantla, where our excavations were made, the valley is
probably not more than 3 or 4 meters above the present level of the lake.
The surface is irregular, partly from the effects of erosion, partly owing
to the removal of considerable masses of soil which have been used for
centuries for the manufacture of adobes. The surface consists of vegetable
mould and decomposed volcanic tufa deposited in the form of
dust. In many places, one or more layers of tepetate are found at a
depth of about 1 meter. This is a calcareous deposit due to the oozing
530out and redepositing of calcareous matter. The tepetate had been used
for buildings in some places, and appears in such combination with
layers of pebbles as to make an artificial origin at least plausible. Mounds
of varying size are found above the tepetate all over the valley, and often
rise over a paved floor, which is almost always accompanied by layers
of tepetate.

At San Miguel Amantla, the deeper layers were examined. In the
first excavation Sr. Gamio found loose decomposed tufa under the
tepetate, and at a depth of about two meters and a half he came to the
foundation of a house. The remains of an excavation and of a large
hearth indicated that at this level the site had been inhabited. Deeper
down followed more decomposed tufa but much more solidly packed,
and fine and coarse sands were found in between. The whole structure
of the deposit indicates that it must be considered as a subaërial deposit
from which the finest particles were washed out by water during wet
seasons, leaving the volcanic sand, which shows, in some places, stratification
due to small watercourses. At a depth of 7 meters the volcanic
tufa ceases almost suddenly and is followed by very coarse gravel alternating
with sand, clearly the remains of a stream which crossed the
valley. The gravel is about 2 meters thick. It also ends suddenly, resting
on a very hard black clay which contains impressions of plants and is
evidently an old swamp. This clay is filled with much decomposed tufa.
Under it is found a whitish sand, a lake deposit. The present water
table, at the end of the dry season, is in the hard swamp clay. A number
of control diggings showed that the swamp had a considerable extension,
and that the gravel bed represents a river 100 meters in width. At the
sides of the river a sandy soil is found in place of the gravel, probably
indicating that more of the fine material was washed away there than in
the higher levels. This old river-bed seems to lie under a former level of
the Lake of Texcoco, which would indicate considerable climatic
changes in the valley of Mexico since the deposition of the swamp clay.

In the region of San Miguel Amantla and Tacuba, Aztec remains are
confined to the mounds and to surface layers. As soon as the undisturbed
decomposed tufa is reached, specimens typical of the culture of Teotihuacan
are found. The remains of houses belong to this type, which persists
to the depth where the river gravel is reached. The remains are
plentiful everywhere, but mostly so on and under the level of the house-foundations.

Still deeper in the gravel, rolled pieces of pottery were found. So far as
531their character can be determined, these do not belong to the Teotihuacan
culture, but are of an entirely distinct technique. Remains of
this kind have been found wherever the gravel of this river course has
been examined. In the swamp and underlying sand no artifacts have
been found. It is, therefore, clear that the decomposed tufa represents
a long period of occupancy by people who had the cultural type of
Teotihuacan, while the Aztec period was very much shorter. If it should
turn out that the geographical and climatic conditions have not changed
considerably since the disappearance of the river course we must assume
a very long time for the Teotihuacan period.

The most difficult question involved in this investigation is the identification
of the cultural type of the river gravel period. The pebbles in
the gravels come from the Santa Cruz mountains, and although the bits
of rolled pottery might have had the same origin, it seemed to me that
many were not sufficiently rounded to have undergone transportation
over long distances in a rapid river filled with pebbles, and for this reason
a search in the valley seemed necessary. In this we were favored by
luck, and Sr. Gamio found objects of this type in his fifth excavation
quite plentifully and in undisturbed position. His finds consist of small
figures and fragments of pottery with painted surfaces. Here he made
the important observation that in the lower sands these older types occurred
with the types of Teotihuacan and that the latter seemed to disappear
in the lowest layers of the sand. It would seem, therefore, that there
has been a gradual transition from the oldest culture to that of Teotihuacan.
We had reached this conclusion before, from the types of small pottery
heads, some of which showed distinct technical affiliations with the
oldest culture. In the Museum at Teotihuacan a number of figurines of
the same type are shown and recently objects of the same class were
found at the lowest levels of the subterranean structures. These finds
were made by Sr. Rodriguez, Inspector-General of Monuments, and
are important because they show that in Teotihuacan also the same
primitive culture occurs.

My own inquiries in the Sierra de Guadalupe enabled us to give a
better identification of this culture. In the autumn of 1911, when searching
with Dr. von Hoerschelmann for some point in the Sierra de Guadalupe
where the Teotihuacan type might occur, our attention was called
to a pile of potsherds on the slope of the hill of Zacatenco, and the
similarity of the types to those of the Cerro de la Estrella, as well as the
difference between these types and the valley types was at once apparent.
532In the course of the following months I succeeded in locating two other
places with the same type in the Sierra de Guadalupe, and further
objects of the same character, although not in such quantity, were
secured from the Peñion de los Baños and Los Reyes. I was able to bring
together a considerable collection of specimens and these are identical
in type with the oldest culture of San Miguel Amantla. The whole
impression of these remains is that they are closely akin to those of the
State of Colima and of parts of Michoacan, so that we may conclude
that a technical culture fairly uniform in its fundamental forms extended
in early times from the Pacific Ocean to the Valley of Mexico, and
northward to the state of Zacatecas.

The principal characteristics of the type of pottery found in the sites
mentioned are: great thickness, frequent occurrence of moulded rims;
designs punched in with a dull point; others painted in red, often with
scratched outlines which the color does not follow evenly; a white slip
with scratched designs; the occurrence of grecques somewhat similar to
those of the Pueblos of New Mexico; feet of very large size, and handles
in form of hands. Small heads are very numerous; they were never
made in moulds, but the various ornaments were built up of bits of clay,
and the eye generally consists of a clay pellet with two impressions made
with the point of a stick. The legs of female figures show enormous
dimensions of the thighs, while those of male figures are thin. Almost all
the figures are naked, but provided with neck, ear, and hair ornaments.
They were painted red and perhaps white. It may be remarked here
that on the eastern slope of the Guadalupe mountains a site was found,
which was covered with the remains of the Teotihuacan type.

Across the Valley, on the Cerro de la Estrella, remains of the oldest
type were found, while at the foot of this mountain, at Culhuacan,
enormous quantities of Aztec pottery occur. Nevertheless, in the ditches
that cross this district, numerous specimens with engraved line designs
are found. Since the bulk of the pottery found here has a character quite
distinct from other Aztec pottery, it seemed desirable to investigate the
succession of types. The characteristic yellow ware of the Valley of
Mexico may be divided into three groups; one, of very fine pottery of
light color with regular delicate line-and-dot designs; a second, a little
coarser, and perhaps a little darker, with broader line-and-curve designs;
and a third type much coarser, and darker in color, with complex
designs which bear evidence of having been executed very rapidly and
carelessly. A number of small excavations which were made by Miss
533Ramirez Castaneda show that at Culhuacan the first-named type is the
most recent. Where the soil has not been disturbed it occurs only in superficial
layers. Deeper down, the third type only is found until the water
table is reached, and it occurs in very great profusion. It seems likely
that the older type of Culhuacan pottery had its prototype in earlier
forms, since the rapidity of execution of the designs cannot be understood
unless we assume that the potters were familiar with certain
definite patterns and executed them with the same rapidity and individuality
as we do handwriting.

Pottery with incised designs was found only in the deeper layers,
although not very plentifully. A few specimens of identical type occur
in the oldest Guadalupe sites, but there is not enough material available
to associate these remains definitely with any cultural period. At the
level of the water table the yellow pottery of the Valley of Mexico
disappears and, farther down, the amount of pottery found is rather
small; all the objects of this level that can be identified have the type of
Teotihuacan. I consider a more thorough search in these deeper layers
very promising, because the muck has preserved objects of wood which
may throw much light upon the ancient civilization. The fact that
objects of pottery are found here as much as 3 meters under the water
table does not necessarily indicate great antiquity, for it may well be
that the so-called “floating gardens” existed in this area for a long time.
A constant sinking of the soil and oozing out at the bottom occurs in
these gardens and would gradually carry the old surface layers to considerable
depths.

The principal results of the archaeological work may thus be summarized
by saying that we have obtained the proof of a very old culture
widely spread in Mexico and antedating the culture of Teotihuacan.
Whether the remains found in the hills indicate a late persistence of this
culture cannot be stated definitely. Later on there followed a long
period in which the culture of Teotihuacan prevailed. Apparently there
was a gradual transition from the first to the second period. No such
transition was noted between the culture of Teotihuacan and the Aztec
culture; the latter seems to have lasted, comparatively speaking, a very
short time. What preceded the oldest culture is not known, for in the
place investigated, no earlier remains have been found. It is quite possible
that in regions located on higher ground outside the limits of the
ancient lake and swamp, the conditions for further research may be
more favorable.534