PREFACE
The background of the present study is as follows. After 1955, when
Philip Drucker and Robert F. Heizer excavated the site of La Venta on a
Smithsonian Institution- National Geographic Society- University of California
sponsored expedition, a number of problems remained to be worked on.    Drucker
(1961) made a study of the area where it was believed the peasant population
that had built and maintained the La Venta site had lived, and Heizer, with
the expert assistance of Howel Williams, made a series of two or three week
trips- usually in January, between semesters- to the Olmec area in search of
the geological sources of the stones used for monumental sculpture at the sites
of Tres Zapotes, La Venta, and San Lorenzo (Williams and Heizer 1965).
Prominent among the examples of monumental Olmec sculpture studied by
Williams and Heizer were the colossal heads. While photographs of most of
these had been published, no really detailed study had been made, and toward
this possible end we recorded them and took numbers of photographs. When,
about four years ago, these data were reassessed, it was obvious that they
had been collected in too casual a way, and that a good deal of necessary
information on one sculptured head or another was lacking. In the summer of
1963, Miss Tillie Smith, then a first-year graduate student at Berkeley, was
commissioned to go to Mexico and complete the recording task. Her investiga-
tion was financed by the Archaeological Research Facility, and the data
recorded by her are part of the permanent field records of that organization.
Many of the photographs which appear in this report were taken at that time.
Notwithstanding Miss Smith's energy and care, the information needed for a
full report was still incomplete, and when the opportunity presented itself
in the Winter Quarter, 1967, for us to take four graduate students on a short
research trip to Mesoamerica, we settled upon the project of completion of the
recording of the Olmec colossal heads and the preparation of this report as
one of our main activities.
Our group, joined in Mexico by Philip Drucker and Howel Williams,
became a party of eight, and during the course of the group's travel all
twelve known colossal heads were observed and studied.
The students had spent two weeks before the trip in an intensive
briefing seminar, learning as much as possible about the heads in order to
determine what information was still lacking. The result of this preparation
was the compilation of a checklist of missing or uncertain data that proved
to be a great help in making efficient use of available time.
- v -
After returning from the Mesoamerican tour (which lasted for one
month) the descriptive sections of the papers presented here were drafted,
illustrations prepared, and the report assembled.   This phase of the work
took another month.  From start to finish, therefore, this study represents
the product (although not the sole one) of a ten-week Quarter devoted to
research.  This program, as outlined above, was experimental, and, in our
opinion, turned out successfully.
The study that follows has been wholly a cooperative project of the
four students. We have helped where we could with information, loaned books
and reprints, critically read first drafts, entered into discussions, encour-
aged the students to persevere when they began to say that they wished they
had never heard of the Olmecs, and arranged for publication, but this does
not alter in any way the fact that this report is wholly theirs.
Many persons and organizations have provided assistance in one con-
nection or another with the project, and we wish to express our deep appre-
ciation to the following:
Dean S. S. Elberg, of the Graduate Division, was especially helpful
in providing a grant from Opportunity Funds to support the trip to Mexico,
as well as some incidental expenses connected with preparing the report.
Without his willingness to approve our project proposal, we would not have
had the opportunity to participate in a research Quarter. This report,
therefore, could not have been written without his support, and we hope that
he will find the study worthy of his approval.
The National Geographic Society, through its Committee on Research
and Exploration, allowed us to use a portion of the funds granted earlier
for archaeological investigations in Guatemala for the Mexican investigation.
Our original plan to excavate the site of Templo de Montezuma at Papalhuapa
(Depto. Jutiapa) was inadvisable due to continued insurgent activity in the
area. We are especially indebted to Dr. Alexander Wetmore, Dr. Melvin M.
Payne, Mr. Edwin W. Snider, and Mr. Richard Stewart of the Society.    Dr.
Matthew Stirling's encouragement has been very helpful to us, and we trust
that, as the discoverer of eight of the twelve colossal heads, he approves
our present effort.
For funds to cover other costs of this research we are grateful for
aid provided by the University of California Associates in Tropical Biogeog-
raphy, through its Director, Professor Herbert G. Baker.
Dr. Michael Coe, Director of the Yale University expedition, was kind
enough to offer us the hospitality of his camp at San Lorenzo Tenochtitlan
on the Rfo Chiquito and to furnish us with useful information when we visited
- vi -
that locality to observe his excavations and examine the recently discovered
colossal head called by us San Lorenzo No. 6.
Dr. Philip Drucker accompanied us on our wanderings and was of great
assistance in making local arrangements. We are especially grateful to him
for smoothing over a particularly uncomfortable confrontation at a native
village (unnamed) in Veracruz.
Dr. Howel Williams continued, as a member of our group, his studies
of the petrography of Olmec monuments, and all of the information on that
subject in this report has been provided by him.
Dr. Ignacio Bernal, Director of the Museo Nacional de Antropologfa in
Mexico City, graciously permitted us to study the colossal head (San Lorenzo
No. 2) now on exhibit there.
Ing. Roberto Gutierrez Gil, Superintendente General de Exploracion,
Zona Sur (Coatzacoalcos) of Petroleos Mexicanos, saved the day (a notably
rainy one) for us by providing a four-wheel drive vehicle and driver to en-
able us to visit Punta Roca Partida, where, on Terron Cagado, we saw columnar
basalts that turned out, unfortunately, not to be the source of the basalt
columns that occur at the La Venta site.
Dr. Richard Randolph, then of Rice University, provided us with
excellent photographs of the San Lorenzo 2 head taken when that specimen
was on exhibit in Houston.
Drs. Willard F. Libby and C. Rainer Berger, Institute of Geophysics,
University of California at Los Angeles, determined the age of two carbon
samples from the La Venta and Tres Zapotes sites, and we express to them our
appreciation for this service. One by-product of the 1967 project has been
the reassessment of the dating of the La Venta site, the results of which
have already been published (Heizer, Graham and Berger 1967).
Mrs. Hazel Wald and Miss Donna Chong have prepared the black and white
illustrations. To all of these we extend our thanks.
Robert F. Heizer
John A. Graham
- vii -