Ceramic analysis in the laboratory
In addition to field review, we analyzed sherds in two laboratory
sessions — January 1988 and August 1991. During the week of January 19-26,
1988, Trejo and Witschey analyzed the material from the 1987 field season, and
in particular, the material from test pits 1 and 2. We made our analysis at the
Cancun office of the Centro Regional de Quintana Roo, INAH. All the material
from the 1987 season was reviewed. In August 1991, we reviewed much of the
remaining material (from the 1988 and 1990 field seasons) at the Ceramoteca
(ceramic depository and laboratory) of the Centro Regional de Yucatán, INAH
(formerly the Centro Regional del Sureste) in Merida. I distinguish between
these two analytical sessions because at the first, in Cancun, the comparative
collections available to us consisted primarily of Postclassic material from the
east coast of Quintana Roo. At the second analysis session, we were able to work
with extensive collections from the entire peninsula, and especially the
collection from Coba described by Robles in his M.A. thesis (Robles 1990). It is
the Coba collection to which Muyil ceramics bear the greatest similarity, and we
took great care to judge the similarities and differences between the Muyil
ceramics and the Coba ceramics.
Ceramics were analyzed by segregating the material from each lot into
distinctive groups, which were then usually identified by comparison with known
ceramic types and varieties in the INAH collections. The use of the type-variety
system by earlier researchers for classifying so much of the Yucatecan material
made it imperative for us to use the same scheme for comparative purposes.
Material from a single test pit was analyzed sequentially by level. In this
manner, we analyzed a very high proportion of all the ceramics from
controlled test pits, and a fair proportion of the remaining material. We
analyzed about 32,000 sherds weighing 190 kg. The greatest proportion of
material not analyzed came from cleaning operations conducted during the
consolidation of Temple 8 in the spring of 1990. By observation (but not by
counting or weighing ceramic types) a very high proportion of this material from
the surface cleaning of Temple 8 consists of Late Postclassic material
(such as Navula Unslipped and Chen Mul Modeled censers) with a fair proportion
of Late and Terminal Classic Puuc Slate wares.
We counted and weighed not only the unidentifiable sherds, but also the
analyzed sherds from each separate type and variety (within the lot) for each
recognizable form. All sherds were weighed with a single portable OhausÔ
digital scale which reads from 0-200 g in 2-g increments and 200-2000 g
in 5-g increments. (There is also a narrow range between two readings for
which the scale alternately flashes two values — such as 10 g and 12 g.
In such cases we recorded the average, 11 g, in accordance with the
manufacturer's instructions.) We zeroed the scale prior to each weighing. The
precision of the scale meant that for most groups of several sherds, we were
able to obtain a relatively accurate reading for the aggregate weight. However,
we draw attention to the fact that the weight of small items, such as a packet
of charcoal grains, a single tiny sherd, or an obsidian blade, is not at all
accurate. In particular, a weight of "zero grams" should be
interpreted as "less than one gram."
When the form of the sherd was recorded, we indicated whether it was a
fragment, rim, neck, base, support, or adorno (modeled element from an
anthropomorphic censer). Reused sherds were labeled with their secondary form
— such as net sinker, pendant, or polisher. The two different form categories
permit us to recall, for example, all the net sinkers made on rim sherds (in
addition to their type and variety, if determinable.)
Drawings of a number of distinctive rims (and necks, bases, and supports)
were also made to capture as much modal data as possible. There were relatively
few sherds in the entire Muyil collection for which this was possible (about
1%). Drawings were made full size in a field notebook. Where possible, a large
circular gauge was used in the laboratory to estimate vessel diameter directly.
Otherwise, the arc of the sherd was drawn in the field notebook and digitized,
and then the vessel diameter was calculated by computer. These two techniques
for estimating vessel diameter were determined to be comparable by recording
both the diameter from the gauge and the arc of the sherd for several sherds.
Frequently, calipers were used to record sherd thickness to the nearest 0.1 mm.
Drawings were then digitized using a SummagraphicsÔ
digitizer with AutoCADÔ
software on an IBM PCÔ
compatible computer. The digitized drawings were then reflected about the vessel
radius and checked against the caliper measurements from the field. They were
then scaled and arranged for presentation where they are shown in Appendix 4.
The collaboration of the researchers with respect to the ceramic analysis
is as follows: Trejo entered the 1987 field season as an experienced staff
archaeologist from INAH with more than a decade of experience in excavating and
analyzing ceramics from the east coast of Quintana Roo. Witschey entered with
little formal training in ceramic analysis and one season of field experience in
the northern Maya lowlands. As a result, all identifications in the 1988
analysis session were made by Trejo. In the 1991 analysis session, Witschey
analyzed 20% of the material (supported by the knowledge and expertise of Trejo
as well as the type collections in the Ceramoteca at Merida), while Trejo
analyzed the remaining 80% by type and variety. Witschey reviewed 100% of the
ceramics that were analyzed and their type and variety determinations and
performed all of the recording, counting, weighing, computer tabulation and
statistical analysis of the material.
© Copyright 2000-2005 Walter R. T. Witschey Page last updated Wednesday, April 02, 2008