38 PECKED, GROUND AND POLISHED STONE. 



flat and well-smoothed stone plate of circnlar shape, three-eighths of an inch 

 in thickness, and measuring a little less than ten inches in diameter. An 

 incised line runs parallel "vvith the circumference, which is further ornamented 

 with nine rather irregularly distributed notches (Fig. 150, graywacke, mound 

 in Alabama). Another specimen of the same character (derived from the 

 same locality) measures only eight inches in diameter, and is ornamented with 

 three engraved parallel rings and twenty-one notches around the periphery. 

 A third elaborately finished stone plate is of a rectangular shape, and bears 

 as ornaments incised lines which run parallel with the sides, forming three 

 rectangles, and six notches on each of the smaller sides (Fig. 151, material 

 and locality the same) . It would be impossible, of course, to state the exact 

 use of such plates, and it remains undecided whether they sei'ved as griddles, 

 or as plates for holding solid food, or for some ceremonial or other purpose. 

 A roughly worked plate of clay-slate, nearly i-ectangular in outline, and meas- 

 uring about seven inches by five, was found in an Indian grave in Tennessee 

 near the skull (No. 16799 of the collection) . This plate and the more elab- 

 orate specimens just described jiossibly were designed for the same use. 



There are further to be mentioned slightly concave perforated plates of dif- 

 ferent sizes and shapes, with angles rounded by the action of the elements 

 rather than by art. They consist of potstone, and Avere obtained from Cali- 

 fornia (Fig. 152, Santa Cruz Island) . The character of the curvature in these 

 Californian plates seems to indicate that they were made from broken vessels. 

 An explanation of their special use is not attempted for the i^resent. 



15. Mortars. — The mortars and moi-tar-like utensils form a particularly 

 rich and varied series in the National Museum, embracing all forms and 

 sizes, from the diminutive cup-shaped stone with a cavity not large enough 

 to hold a hazelnut, and apparently used for grinding pigments, to the 

 ponderous deeply hollowed vessel designed to withstand the operation of the 

 heavy stone pestle. The cultivation of maize among the aboriginal tribes 

 spread over the eastern area of the present United- States necessitated the 

 application of grinding utensils, which are, therefore, not unfrequently found 

 on the sites of their former settlements. They are stone slabs or boulders 

 exhibiting shallow concavities, or real mortars hollowed to a depth sufficient 

 to hold a quantity of the cereal. It is shown, however, by the occurrence of 

 circular cavities in projecting ledges of rocks, or in large immovable boulders, 

 that the aborigines sometimes dispensed with portable mortars. Such station- 

 ary contrivances for triturating grain have been noticed in many localities where 

 the Indians formerly dwelt. They used also large Avooden mortars hollowed 

 with the assistance of fire, as described by Adair in his "History of the 

 American Indians" (p. 416). Some Avooden mortars, made by the Iroquois, 

 may be seen in the ethnological department of the JSTational Museum. They 

 are cylindrical, twenty-six inches high, and a little more than fifteen in diame- 

 ter. The rounded cavity has a depth of about one foot. The Avooden pestles 



