96 
BUREAU OF AMERICAN ETHNOLOGY [Bull, 177 
when Mabaruma Plain is the most common, the majority of the Aruka In- 
cised sherds has that paste; whereas in the upper part of the sequence the 
incision is most frequently found on the paste of Hosororo Plain and Koberimo 
Plain, the popular plainwares of the late Mabaruma Phase. See these pottery 
type descriptions for details of temper, texture, and color. 
Surraces: Both in color and treatment, the surfaces are typical of the respective 
plainwares; there is no better treatment or handling of the surface than that 
represented by the better finished plain sherds. 
FORM: 
Rim: Direct with rounded or slightly tapered lip; unthickened and everted 
with rounded lip; interiorly thickened, or exteriorly thickened, with 
rounded or slightly tapered lip. 
Body wail thickness : 4-10 mm. ; majority.5—6 mm. 
Body diameter : 12-36 cm. 
Base: Those forms typical of the plain pottery types: flat, flat pedestal, 
and annular; flat the most common. 
Major vessel shapes reconstructed from sherds : 
ae 
Open bowls with outslanting to vertical sidewalls, direct rim, 
usually rounded but sometimes slightly flattened or tapered lip. 
Mouth diameter 18-26 cm. Incision on exterior; rarely, on interior 
(fig. 38-1). 
. Bowls with sharply everted, unthickened rim and rounded lip. The 
sidewalls range from almost vertical to incurving, but the rim is 
always strongly everted producing an insloping band 1-2 cm. wide 
with an incised design on the inner face. Mouth diameter 16-26 em. 
Incision on inner rim surface (fig. 88-2). 
. Open bowls with interiorly thickened rim and tapered lip. The rim 
is 1-8 mm. thicker than the body wall, and 1.38-2.0 em. wide. Incised 
designs are restricted to the inner surface of this thickened rim area. 
Mouth diameter 12-26 em. (fig. 38-3). 
. Bowls or jars with incurving sidewalls, constricted mouth, direct 
rim, typically rounded but sometimes slightly tapered lip. Mouth 
diameter 9-24 em. Incision on upper exterior (fig. 38-4). 
. Bowls or jars with constricted mouth, incurving side walls and ex- 
teriorly thickened rim with either rounded or slightly tapered lip. 
Rim thickness 6-12 mm., rim width 1.0-2.2 cm.; mouth diameter 
12-36 em. Incision on upper exterior (fig. 38-5). 
DECORATION (pls. 21, 22, 23, h-k). 
Technique: The incised lines are smooth and well made, with a broad, 
U-shaped channel. Width varies from 1.5-3.0 mm., with the majority 
2 mm.; depth ranges from 1.0-1.5 mm., with the majority 1 mm. The 
incisions were made when the clay was medium dry, neither too dry nor 
too wet, and as a result the lines are clean cut and unusually even. A few 
are less carefully done, suggesting individual variation and careless 
workmanship, which is not characteristic of the type. So-called “parallel 
lines” were made with individual strokes and hence these lines are not 
always exactly parallel. 
Motif: Five distinct design motifs are characteristic. Since only one com- 
plete vessel and a few large sherds were found that showed the overall 
pattern of decoration, it is possible that two or more of these motifs are 
often combined on the same vessel. 
1. Unzoned, rectilinear incisions, commonly in paired units or parallel 
lines (pl. 21, a, b). 
