mindeleff] 



STRUCTURAL FEATURES. 311 



The floors of the rooms, which were also the roofs of the rooms below, 

 were of the ordinary pueblo type, employed also today by the Ameri- 

 can and Mexican population of this region. In the Casa Grande ruin 

 a series of light joists or heavy poles was laid across tlie shorter axis 

 of the room at the time the walls were erected; these poles were 3 to 6 

 inches in diameter, not selected or laid with unusual care, as the holes 

 in the side walls which mark the places they occupied are seldom in a 

 straight line, and their shape often indicates that the poles were quite 

 crooked. Better executed examples of the same construction are often 

 found in northern ruins. Over the primary series of joists was placed 

 a layer of light poles, li to 2 inches in diameter, and over these reeds 

 and coarse grass were spread. The i)riuts of the light poles can still 

 be seen ou the walls. The floor or roof was then finished with a heavy 

 coating of clay, trodden down solid and smoothed to a level. A number 

 of blocks of this final floor finish, bearing the impress of the grass and 

 reeds, were found in the middle room. There is usually a setback in 

 the wall at the floor level, but this practice was not followed in all the 

 rooms. 



The position of the floor is well marked in all cases by holes in the 

 wall, into which beams projected sometimes to a depth of 3 feet, and by 

 a peculiar roughness of the wall. Plate LVi shows two floor levels, 

 both set back slightly and the upper one strongly marked by the rough- 

 ness mentioned. This roughness apparently marks the thickness of the 

 floor in some cases, yet in others it is much too thick for a floor and 

 must have had some other purpose. The relation of these marks to the 

 beam holes suggests that in some cases there was a low and probably 

 narrow bench around two or more sides of the room; such benches are 

 often found in the present Pueblo villages. 



The walls of the northern room are fairly well preserved, except in the 

 northeastern corner, which has fallen. The principal floor beams were 

 of necessity laid north and south, across the shorter axis of the room, 

 while the secondary series of poles, IJ inches in diameter, have left 

 their impression in the eastern and western walls. There is no set- 

 back in the northern wall at the first floor level, though there is a very 

 slight one in the southern wall; none appears in the eastern and west 

 ern walls. Yet in the second roof level there is a double setback of 9 

 and 5 inches in the western wall, and the northern wall has a setback 

 of 9 inches, and the top of the wall still shows the position of nearly all 

 the roof timbers. This suggests — and the suggestion is supported by 

 other facts to be mentioned later — that the northern room was added 

 after the completio)i of the rest of the edifice. 



The second roof or third floor level, the present top of the wall, has 

 a decided pitch outward, amounting to nearly 5 inches. Furthermore, 

 the outside of the northern wall of the middle room, above the second 

 roof level of the northern room, is very much eroded. This indicates 

 that the northern room never had a greater height than two stories, but 

 probably the walls were crowned with low parapets. In this counec- 



