If we adopt the idea that they were the residences of the chiefs of the people, the mystery does not seem so great. If the circular wigwam of the chief was erected in the centre of the circles, and the wigwams of his subordinates and retainers in concentric circles around him, it would account for their dimensions, and also for the disappearance of all traces of habitation. The forecourt would thus be the place of assembly of the tribe, the exercise ground or gymnasium, and for such purposes it is admirably adapted, and both the size and the situation of these enclosures seem easily explicable.
One curious circumstance tends to render this view more tenable. On plate xxi. of Messrs. Squier and Davis's work four groups of squares with circles are delineated, situated in different parts of the country; but all the four squares are almost identical in size, each side measuring 1080 feet. Why four temples should be exactly alike is a mystery, but that a tetrarchy of chiefs should be bound down to equal dimensions for their rival residences seems reasonable from a civil point of view.
It does not seem difficult to explain the meaning of the inside ditch when fortification was not intended, as it must have been almost a necessity with a people who had not arrived at the elevation of using brick drains or drain-pipes. Without some such arrangement all the rain that fell within these solid enclosures would have remained on the surface, or in the squares could only have escaped through the openings, but a deep and broad ditch all round would drain the whole surface without inconvenience, and secure the only mode which would prevent the enclosure, be it a temple or palace, from becoming a swamp.
Messrs. Squier and Davis divide the conical mounds which they excavated into two classes. The first they call "Mounds of sacrifice," because on digging into them they found on the level of the soil what appeared to be altars — raised floors which exhibited evidence of intense heat, and what they considered a long-continued practice of burning. It is evident, however, that such results might be produced in a week as well as in years, and it is very difficult to understand why at any time that which had been an altar should be buried in a tumulus. If it had been used for years, why, and on what occasion, was it agreed to bury it? If
