490 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1916. 



ward and a depression a few inches deep in the top, which usually 

 shows signs of extreme heat. These altars are of various sizes, but 

 usually the cavity or depression is about 3 feet in diameter. In the 

 larger mounds, which have been sj^stematically explored, notably 

 those of the Porter, Hopewell, Turner, and Liberty groups a consid- 

 erable number of skeletons were found in the same mounds with the 

 altars. The number of altars occurring in a single mound ranged 

 from one to four. It is from the altars that many of the objects de- 

 scribed in this paper were taken. Other specimens illustrated were 

 found with skeletons or in deposits near them. 



SYMBOLIC EARTHWORKS 



Among the most interesting of the earthworks, when regarded in- 

 dependently of the artifacts they contain, are the effigy mounds, 

 which appear to be related symbolically to certain objects recovered 

 from the tumuli. A brief notice of some of them may be of interest. 



The Serpent Mound of Adams County is the best known of the few 

 earthworks of this class. The illustration of this work shown on 

 plate 1, i, is reproduced from Prof. Holmes's drawing, made in 1886, 

 and undoubtedly represents the effigy much as it appeared to its 

 builders. MacLean's plan, made from careful surveys in 1885, agrees 

 with the above very closely, the principal difference being in the 

 broadening of the extreme projection in front of the oval and the 

 adding of two small spurs thereto. Squier and Davis's drawing is 

 incorrect in several respects, and seems to be more like a sketch-plan 

 made without surveying instrument than the accurate survey claimed 

 by them. In the Peabody Museum of Harvard University there is an 

 unfinished plan from a survey made by Thomas P. Gore, of Hills- 

 boro, Ohio, in 1878, which corresponds to those of MacLean and 

 Holmes with the exception of the wishbone-shaped section in front of 

 the oval which is not indicated. In this plan the embankments upon 

 either side of the rear half of the oval which connect with that of the 

 triangular inclosure appear as shoAvn by both MacLean and Holmes. 

 Portions of these, and the wishbone-shaped embanlanent inclosing 

 the front of the oval, were much less conspicuous than the oval and 

 the main portion of the serpent. These were not considered by Prof. 

 Putnam as parts of the effigy at the time of its restoration. Before 

 entering into details regarding the peculiar features of this earth- 

 work, I desire to call attention to the serpent head wrought from cop- 

 per shown in plate 1, k, which was found with many other copper 

 objects in the great mound of the Hopewell group. 



As is well known to anthropologists, the serpent occupied a promi- 

 nent place in the religious life of many tribes north of Mexico, as 

 well as in Mexico and Central America, and it appears in combina- 

 tion with the cosmic symbol, or some of its parts, in various sections. 



