46 ANTIQUITIES OP WISCONSIN. 



site.^ No ridge exists along the river bank, as represented on Mr. Hyer's plan; the 

 steepness of the bank probably rendering artificial works unnecessary for the pur- 

 poses of the builders. Some of the interior ridges, it will be observed, are enlarged 

 at intervals ; thus showing an analogy with the main walls and outworks. 



There are two excavations (e and/), the first triangular, and the last circular, 

 which, from their greater depth and regular shape, as well as distance from the walls, 

 were probably not made in the process of obtaining materials for the structures. 

 The excavation at e is so deep, and the soil so tenacious, that water 'stands in the 

 bottom much of the time, affording a place for the growth of flags^ and other 

 aquatic plants. Perhaps the bottom may have been rendered water-tight by arti- 

 ficial means. Undoubtedly it was once much deeper than at present ; the tendency 

 of rains and the accumulation of vegetable matter being to fill it up. The circular 

 excavation (at /) is surrounded by a ridge consisting, doubtless, of the materials 

 thrown out in the digging. 



Near this point are some springs in a small ravine cut into the bank by the pas- 

 sage of water to the river. This ravine serves also as the outlet of the surface 

 water from within this part of the inclosure. A few stones left along the sides and 

 bottom of this ravine (the force of the water not being sufficient to remove them 

 with the hghter particles of the earth), is all the evidence that could be found of 

 an ancient sewer "arched with stone." It is quite clear that no such arch existed ; 

 nor is there any indication that the aboriginal inhabitants of the American con- 

 tinent were acquainted with the nature of the arch.^ If they were, they certainly 

 did not apply such knowledge in the construction of any works at Aztalan. 



* We are told by Catlin that " the village of the Mandans has a most noTel appearance to the eye of 

 a stranger ; their lodges are closely grouped together, leaving just room enough for walking and riding 

 between them, and appear from without to be built entirely of dirt. They all have a circular form, and 

 are from forty to sixty feet in diameter. Their foundations are prepared by digging some two feet in 

 the ground, and forming the floor of earth by levelling the requisite space for the lodge. The super- 

 structure is then produced by arranging inside of this circular excavation, firmly fixed in the ground 

 and resting against the bank, a barrier, or wall of timbers, about six feet high, placed on end, and 

 resting against each other, and supported by a formidable embankment of earth raised against them 

 outside. Resting on the tops of these timbers are others of equal size, rising, at an angle of 45°, to the 

 apex or sky-light, which is about three or four feet in diameter, answering also as a chimney. On the top 

 of or over these poles or timbers, is placed a complete mat of willow boughs, of half a foot or more in 

 thickness, that protects the timbers from the dampness of the earth with which the lodge is covered 

 from bottom to top, to the depth of two or three feet", having above all a hard or tough clay which is 

 impervious to water." — N. Am. Indians, I, 81. 



* Iris versicolor. 



Fig. 15. 



Arched Door, Uxmal (Stephens). 



= Even in Yucatan and Central America, where the aboriginal buildings display the greatest advance 

 in architecture, the arch was not used ; its substitute being stones laid horizontally, and made to overlap, 

 as represented in Fig. 15.— Stephens's Yucatan, I, 429. 



