An initial examination of the pottery assemblage from Motupore Island revealed two major obstacles to
132 P O T T E R Y T E C H N O L O G Y
reconstructing forming proceSs sequences. First, the sample of sherds was selected by the archeologist for stylistic and morphological attributes. This meant that sherds with unusual fracture patterns and other evi dence of forming techniques were unlikely to be repre- sented. The second and more serious difficulty was that most of the surface evidence of forming technique was difficult to interpret or had been obliterated by later operations, such as smoothing. As a result, it was decided to use X-rays. Different forming techniques should produce distinctive orientations of inclusions, which could be seen in the radiographs (Rye 1977).
Establishing Standards. The first stage of inves- tigation was to collect pottery made by Papuan tradi tional potters and to record in detail their forming techniques. V essels from co llectio n s made in Melanesia by other ethnographers were included. Since the forming techniques were known, the pre ferred orientation o f inclusions revealed by the X-radiographs could be recognized, establishing a ref- erence against which unknown archeological vessels could be compared. Ali the major forming techniques employed by traditional Melanesian potters were rep- resented: drawing, coiling, beating, beater and anvil, pinching, and various methods of rotation.
Analyzing Sherds. Once the standards were available, a sample of about 300 sherds from the Motupore exeavations was selected for initial exami- nation. The main basis for selection was size; it was anticipated that larger sherds would facilitate recogni- tion of preferred orientation and the initial trials showed this to be the case. Within the minimum size, an attempt was made to include sherds representing as many vessel shapes as possible. No distinction was made between rims, bases, and body sherds; ali were considered equally relevant.
The sherds were sorted first according to thick ness. Ali those on the same radiograph must have the same thickness to insure uniform exposure (R ye 1977:210). Film 14 by 17 inches (35.6 by 43.2 cm) was used, allowing up to 10 sherds to be exposed on each film.
The following information was tabulated for each sherd: site, levei, and sherd number; particle-size dis tribution of inclusions; preferred orientation; fracture; visual description (including any attributes useful for inferring forming techniques), and a “ diagnosis” of forming techniques. The techniques were arranged in a coherent process sequence for each sherd.
Groups of Process Sequences. Seven groups of process sequences were distinguished. The first two correlate with globular vessels: the others were used to
Fig. 116. Sherd from the Motupore site with anvil impressions on the interior.
produce open bowls. The groups have the following characteristics:
Group l . Bali of clay drawn upward to form thick walls. Rim formed and smoothed by pinching com- bined with rotation. Walls and rounded base formed using a beater on the exterior opposed by the potters other hand on the interior (fingertip impressions com mon on the interior walls).
Group 2. Same as Group 1, except that during beating an anvil was used on the interior to oppose the force of the blows (Fig. 116).
Group 3. Initial form produced by pinching. Rim formed and smoothed by pinching combined with rota tion. Both surfaces scraped; interior then smoothed.
Group 4. Initial form produced by pinching. Rim formed and smoothed by pinching combined with rota tion. Interior smoothed with fingers while clay still soft. Exterior scraped, then smoothed.
Group 5. Base pinched and drawn. Coils added to rim to increase height. Rim formed and smoothed by pinching combined with rotation. Interior and exterior smeared to bond coils, then smoothed.
Group 6. General form produced by coiling. Rim formed and smoothed by pinching and rotating be tween fingers. Interior and exterior scraped, then smoothed.
Group 7. General form produced by coiling. Rim formed and smoothed by pinching and rotating be tween fingers. Interior and exterior scraped; interior then smoothed.
Comparison of these groups shows that some are very similar. Groups 1 and 2 are identical except for the type of “ anvil” used on the interior. Groups 3 and 4 are similar except for the extent of smoothing of the surface: Groups 6 and 7 are similarly related. Only Group 5 is distinct. The process sequences can therefore be combined into four major categories, with
minor variations in three of these. The variations are important because they produce vessels with distinc tive appearances; the difference between a scraped and a smoothed surface is visually very obvious.
The process sequence represented by Group 2 is identical to that I observed among present-day potters in Boera, some 30 km from Motupore. No observa- tions have been made of techniques for making bowls. The bowl form so common in archeological sites ap- pears to have been replaced by metal, plastic, and im- ported glazed ceramic vessels.
Chronological Differences. In order to establish whether changes in process sequences occurred through time in the Motupore site, the distributions of sherds in each group were examined by stratigraphic levei. The frequencies of the sherds assigned to each group were calculated in two ways: ( ! ) as a percentage of the total sherds in each levei and (2) as a percentage of the sherds in the group (Table 5). In Levei II, for exampie, 70 percent of the sherds belonged to Group 2; these represent 12.5 percent of the total number in Group 2.
Statistical analyses have not been attempted be cause of the inadequate size of the samples from some groups and stratigraphic leveis, but some interpreta- tions are suggested by the data:
Group I is much less common than Group 2, from which it differs only in the substitution of the potter’s fingers for an anvil. This implies that Group 2 is the primary process sequence and Group I a minor variant.
Group 5, which represents a distinctive technique, contains only 3 sherds, which come from Leveis I and III. Their rarity makes it desirable to include these sherds in studies of materiais to determine if they were made elsewhere. If they were imported, the contact appears to have occurred late during the occupation, but the sample is too small for this to be certain.
If ali the pottery in the sample was made on Motu pore Island, the high frequency of Group 2 vessels might be interpreted as indicating this forming process was the most common. This inference is suspect, how ever, because larger vessels produce larger sherds and the sample was selected on the basis of sherd size, introducing a possible bias.
The data suggest the number of process sequences used to form bowls increased. If Groups 1 and 2 are combined and Groups 3-7 are combined, the ratios of bowls to jars remains relatively constant. Although the relative proportions of bowls and globular vessels do not change significantly, the relative distributions of bowl-forming process sequences change considerably. The Group 4 sequence is the predominant or only method in Leveis V I through IX . Group 7 appears first in Levei V II and Group 6 in Levei V I. These patterns may indicate that potters were using more specialized techniques to produce bowls, but whether the dif ferences in surface finish thatdistinguish related groups refiect changing esthetic tastes or functional specializa- tion cannot be established at present.
These preliminary results are suffi ient to demon-
Table 5. Relative frequencies of forming process sequence groups by stratigraphic levei at the Motupore site, Papua New Guinea. N = size of sample; Arabic numbers = percentage of total in levei; Italic numbers = percentage of total in group.____________________________________
Forming Stratigraphic Leveis
N
Sequence
Groups I II III IV V VI VII VIII IX X
1 0 0 18.2 0 0 0 0 36.4 0 45.4 0 0 4.4 0 0 0 0 6.8 0 35.7 11 2 8.3 12.5 16.7 6.0 3.0 10.7 7.7 28.0 1.7 5.4 56.0 70.0 62.2 76.9 83.3 69.2 65.0 79.7 60.0 64.3 168 3 6.7 133 13.3 0 0 13.3 26.7 26.7 0 0 4.0 6.7 4.4 0 0 7.6 20.0 6.8 0 0 15 4 16.7 8.3 20.8 8.3 0 12.5 8.3 16.7 8.3 0 1 6.0 6.7 11.1 15.4 0 11.5 10.0 6.8 40.0 0 24 5 33.3 0 66.7 0 0 0 0 0 0 0 4.0 0 4.4 0 0 0 0 0 0 0 3 6 29.4 23.5 23.5 5.9 5.9 11.8 0 0 0 0 20.0 13.3 8.9 7.7 16.7 7.7 0 0 0 0 17 7 0 20.0 40.0 0 0 20.0 20.0 0 0 0 0 3.3 4.4 0 0 3.8 5.0 0 0 0 5 N = 25 30 45 13 6 26 20 59 5 14 243
134 P OTTER Y T E C H N O L O G Y
strate that using X-ray techniques for observing pre ferred orientation of inclusions greatly expands the po- tential for forming studies. Whereas initial inspection allowed reconstruction of forming techniques for only about 10 percent of the sherds, the use of radiographs increased the figure to about 85 percent. The basic requirement for more detailed studies is samples of statistieally reliable sizes.