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PROCEEDINGS OF THE NATIONAL MUSEUM 



line, if the object be rolled back at a slightly different angle but without 

 lifting it from the clay, a second line of indentations results. This 

 procedure, repeated indefinitely, produces a band of "dentate rocker" 

 impressions that duplicate in every essential the markings on sherds 

 actually found at the Trowbridge site (cf. figs. 50, a, and 50, b). 

 In the sherd illustrated (fig. 50, b) the markings made by the native 

 potter differ from those produced on plasticine in the laboratory (fig. 

 50, a) in being more closely spaced and somewhat deeper. The greater 

 depth is probably due to the use of a sharper or less worn tool. 



a 





3 



Figure 50. — Impressions produced on plastic clay (a) by roulette, compared with rouletted 

 sherd (6) from Trowbridge site, Wyandotte County, Kans. 



From our experiments and field observations, we are led to believe 

 that this type of tool, with certain easily made variants, was in general 

 use among the potters of the Trowbridge, Renner, and culturally re- 

 lated sites of the Kansas City area. The off-center and oblique 

 placement of the handle, together with a slightly elongate wheel, forms 

 an ideal combination for making curved rocker impressions. Smooth 

 or edentate rocker marks, which decidedly ])redominate over the 

 dentate style in this locality, could have been produced with an iden- 

 tical implement from which the rim notches had been omitted. 

 Owing to the eccentric placement of the handle, a continuous indented 

 line tends to be wavy and undulating, though an experienced operator 

 would probably have better success than we. But this difficulty could 

 be easily remedied: a centrally placed handle at right angles to the 

 plane of the working edge would permit the easy production of straight 

 lines of any desired length. Given the essential idea, as in the present 

 specimen, it is within the bounds of reason and probability that the 

 variants, though not yet recognized in the local archeology, were 

 known and used in aboriginal times. 



