From Dean Wilson and the Southwest Pottery Typology Project: Chaco PII PIII Corrugated as defined here is characterized by rim sherds with indented and plain clapboard corrugations exhibiting a rim eversion between 30 to 60 degrees (Reed and others 1998). This group is based on the range of rim eversion originally utilized to define Dolores Corrugated and may include pottery previously assigned to Tseh So Corrugated and Coolidge Corrugated. Pottery assigned to this group are extremely rare at contexts dating prior to A.D. 1000, and became more common during the end of the eleventh century, at which time most corrugated vessels displayed such eversion. Such forms declined through the twelfth century. Only rim sherds were assigned to this type as body sherds were assigned to descriptive types based on characteristics noted for coils.