324 REPAIR OF CASA GRANDE RUIN (eth. ajw. 15 



earth from tlic iiniia'diuto site. In tlio finistniclioii of the walhs this 

 soil was laid up in successive courses of varyiug thickness, whose 

 limits form ck'arly detinetl and apiiroxiniatcly horizontal joints. The 

 uortlu-ast and southeast corners of the building have entirely fallen 

 away, and low mounds of their debris still show many kii()l)s and 

 lumps, ])arts of the orijjinal wall mass. 



The destruction of tlie walls was due mainly t<i undermining at the 

 ground level. The character of this undermining is shown in many of 

 the illustrations to this report, es])ecially in plate cxvr, and its extent is 

 indicated on the aceoinj)anying ground i)lan (i)latecxvii) by dotted lines 

 within the wall mass. Although the material of which the walls are 

 composed is very hard when dry, and capable of resisting the destruc- 

 tive influences to which it has been subjected for a long time, yet under 

 certain comlitions it becomes more yielding. The excessively diy cli- 

 mate of this region, which in one respect has made the i^reservation of 

 the ruin possible, has also furnished, in its periodic sandstorms, a 

 most eflicient agent of destruction. The amount of moisture in the 

 soil is so small as scarcely to be detected, but what there is in the soil 

 next to the walls is absorbed by the latter, rising doubtless by capil- 

 lary attraction to a height of a foot or more from the ground. This 

 portion of the wall being then more moist than the remainder, although 

 possibly only in an infinitesimal degree, is more subject to erosion by 

 flying sand in the windstorms so frequent in this region, and gradu- 

 ally the base of the wall is eaten away until the supjiort becomes insulti- 

 cient and the wall falls en masse. The plan shows that in some places 

 the walls have been eaten away at the ground level to a dei)th of more 

 than a foot. Portions of the south wall were in a dangerous condition 

 and likely to fall at any time. 



Visiting tourists have done much damage by their vandalism. They 

 have torn out and earned away every lintel and every particle of visible 

 wood in the building. After the removal of the lintels a comparatively 

 short time elapses before the falling in of the wall above, .\pparently 

 but a small amount of this damage can be attributed to rainstorms, 

 which, although rare in this region, are sometinu's violent. There is 

 evidence that tlie present height of the walls is nearly the original 

 height, in other words, that the loss from surface erosion in several cen- 

 turies has been trifling, although numerous opinions to tlie contiary 

 Lave been exjiressed by causal observers. The eastern wall has suf- 

 fered more from this cause than the others; a belt on the northern 

 half, ajiparently softer than the remainder of the wall, has been eaten 

 away to a depth of nearly a foot. The interior wall faces are in good 

 condition generally, except about oiieniiigs and in places near the top. 



Evidences of the original flooring are jireserved in several of tiie 

 rooms, especially in the north room. The flooring conformed to the 

 pueblo ty])e in the use of a series of principal beams, about 3 inches in 

 diameter, above which was a secondary series smaller in size and placed 



