218 . 



CERTAIN SAND MOUNDS OF 



composed of seven bars, while in the lower figures there are eight in the correspond- 

 ing space. 



" On this plate also the carbonate forms a thick coating, and interferes with a 

 thorough examination. However, a close scrutiny shows the plate to be made of 

 two sheets overlapping along the margin. The larger sheet had been split to the 

 depth of about half an inch near the middle of one edge, and into this slit had been 

 inserted the edge of the smaller sheet, so that one-half of the margin of each sheet 



Fig. 77. Lower plate, copper breast-piece, showing use of rivets, Mt. Royal. (Half size.) 



overlapped on one surface and the other half on the opposite surface. In this 

 position they were riveted together. 



" The arrangement is indicated on Fig. 77, in which the line A, B, represents 

 the margin of the smaller sheet inserted into the split edge of the larger sheet at C. 

 The heavy portion of the line, A, C, indicates the free margin of the smaller sheet 

 on the presenting surface of the plate, while the dotted portion, B, C, is the con- 



