THE ANCIENT PEOPLES. 4] 
the fillet with some attention to regularity and rhythm 
patterns were produced, sometimes highly decorative. 
This style of pottery, known as corrugated, is found 
over the entire Southwestern area. In the matter of 
time it has been shown that corrugated pottery began 
with the inhabitants of pit or slab houses who used wide 
filaments about the upper portion of the vessels. It 
did not reach its finest stage until a fairly late period 
and continued to be made until about 1680. These 
Prehistoric Coiled Ware. 
vessels were used generally, perhaps solely, for cooking 
purposes. On the upper Gila a distinct type of cor- 
rugated pottery, which seems to be of local origin rather 
than to belong to any definite period, has very narrow 
filaments of clay and is made with great skill. The 
interior of the vessels is highly polished. 
For purposes other than cooking, another type of 
pottery known as black on white was used over the 
entire area from the earliest times until shortly after 
the Spaniards arrived. A white, or white modified to a 
gray or pink slip is over the entire surface of the vessel, 
