The Repair Of Casa Grande Ruin, Arizona, in 1891 Part 5

Sir: Pursuant to your request of September 12, 1895, Mr W J McGee, ethnologist in charge in the Bureau of American Ethnology, will in a few days repair to Florence, Arizona, for the purpose of examining Casa Grande ruin and determining the desirability of further works for its preservation. * * *

In accordance with terms of preceding correspondence, it is of course understood that the cost of the work will be borne wholly by this Bureau.

I have the honor to be, yours, with great respect,

J. W. Powell, _Director_.

The Secretary of the Interior, _Was.h.i.+ngton, D.C_.

VI. _Report of the Director of the Bureau of American Ethnology to the Secretary of the Interior on the examination of the condition of Casa Grande by Mr W J McGee, with a recommendation concerning its further protection_

Smithsonian Inst.i.tution, Bureau of American Ethnology, _Was.h.i.+ngton, November 15, 1895_.

Sir: Pursuant to a proposal made in connection with a report from this office relating to the ruins known as Casa Grande, near Florence, Arizona, under date of August 28, 1895, and to the acceptance of this proposal in a communication from the Department of the Interior under date of September 12, 1895, Mr W J McGee, ethnologist in charge of the Bureau of American Ethnology, has within a few days made an examination of Casa Grande ruin with the view of determining the need for further protection of the ruin by a roof or otherwise.

There are in this office two series of photographs representing the ruin. The first series was taken in 1892 before the protective works authorized by the Congress were commenced; the second series represents the work in progress. In the recent examination the present condition of the ruin was carefully compared with the condition represented in the photographs.

On comparing the profiles of the walls, it was found that in many cases the irregular upper surfaces retain the exact configuration of 1892, even to the slightest k.n.o.bs and rain-formed crevices; the correspondence being so close as to show that the injury and loss by weathering during the interim has been imperceptible. In some other cases, notably along the southern and eastern walls, the profiles are more extensively modified; some of the points and k.n.o.bs shown in the photographs are gone, some of the old crevices are widened and deepened, and some new crevices appear; and in some parts it can be seen that walls are lowered several inches. On the whole the modification of the profiles of the walls is limited, yet such as to indicate that destruction is proceeding at a not inconsiderable rate.

On comparing the scars and crevices on the sides of the walls, it was found that, while many remain essentially unchanged, most are enlarged and deepened. This is particularly noteworthy on the eastern and southern walls, which are most beaten by wind-driven rains, and which are also most modified in profile. It would appear that destruction is proceeding more rapidly along the sides of the walls than along the crests.

On examining the walls with respect to apparent solidity and stability, it was found that nearly all are in fair or good condition. The only portion that would seem in special danger is the central section of the southern exterior wall. This section seems insecure, and might at any time be overthrown by a heavy wind following a rain storm. This section was not, unfortunately, braced or tied to the stronger interior wall when the protective works were carried out in 1892.

On examining the structure to ascertain the effect of the protective works of 1892 in staying the destructive processes, particularly the undermining of the walls by spattering rain and drifting sand, it was found that in most cases the results have been excellent. On the inner side of the middle section of the southern exterior wall sapping is in progress at the ground level, and also along the rows of joist openings for the first and second stories, and in a few other places the protection seems inadequate; but in general the antic.i.p.ations of the projectors of the protective works seem to have been realized.

The most serious of the destructive processes was sapping, and this process has been nearly checked by the protective works. The second was the desurfacing and subsequent eating away of the walls by beating rains and frost, and this is still in progress at a moderate rate. The least serious process was the wearing away of the crests of the walls by rain and winds, and this is still going on at a perceptible rate. It is impossible to determine, and difficult even to approximate, the rate of destruction quant.i.tatively, especially so since it goes on c.u.mulatively, with constantly increasing rapidity, as the cemented surfaces are destroyed and the crevices widen and deepen; but judging from the history of the ruin, and from the rate of destruction indicated by comparing the photographs of 1892 with the present aspect, it would seem safe to conclude that, if protected completely from vandalism, the ruin will be comparatively little injured during the next five years, and will stand perhaps half a century, without further protective works, before moldering into dust.

In view of the slow yet ever increasing rate of destruction of the ruin, and of its great interest as a tangible record of the prehistoric inhabitants of this country, no hesitation is felt in recommending that the structure be further protected, and practically perpetuated, by a suitable roof, so designed as to s.h.i.+eld the walls from rain and sun and at the same time permit an un.o.bstructed view of the ruin from any direction.

I have the honor to be, sir, yours, with great respect,

J. W. Powell, _Director_.

Secretary of the Interior.