It is not clear that a roof is absolutely necessary, but it is certain that it would be very undesirable.  The region where this rain occurs has probably less rainfall than any other part of the United States, but it must not be forgotten that while rainstorms are infrequent they are sometimes violent, and what damage they do may be done in a few hours.  All the items for the repair of the ruin, except that pertaining to a roof, were so devised that the ruin was not materially disfigured or changed, and were they fully carried out the ruin would present much the same general appearance as before.  It is important that this appearance should be preserved as far as possible, but it can not be maintained if a roof is erected over the walls.  As four years have elapsed since the completion of the work, it should be possible now to determine whether atmospheric erosion has played a material part in the work of destruction.[1]

[Footnote 1:  See the letter of the Director of the Bureau of American Ethnology to the Secretary of the Interior regarding the examination of Casa Grande by Mr W J McGee in the supplement to the present paper.]

In the original plans and in the specifications which formed part of the contract (although this section was not operative) a plan for a roof was included.  Such a structure, if erected at all, should be made as inconspicuous as possible and should be supported entirely from within the building.  The system of framing employed might safely be left to the contractor if he were made responsible for the strength of the completed structure.

RESERVATION OF THE LAND

The final step in the execution of the law quoted was taken June 22, 1892.  On that date the recommendation of the writer to the Director of the Geological Survey, referred by him to the Secretary of the Interior and by the latter to the President, was finally approved, and it was ordered that an area of land sufficient for the preservation of the ruin, and comprising in all 480 acres, be reserved under authority of act of Congress approved March 2, 1889.  This area is shown on the map reproduced in plate CXXV, the base of which is a map accompanying the report of Mr H. C. Rizer.

The letter of the Secretary of the Interior recommending the reservation of the Casa Grande tract, with its indorsement by the President, is as follows: 

  Department of the Interior,
      Washington, June 20, 1893.

Sir:  I have the honor to recommend that the SW. 1/4 SW. 1/4, Se. 1/4 SW. 1/4, SW. 1/4 Se. 1/4 section 9, NW. 1/4, NW. 1/4 NE. 1/4, SW. 1/4 NE. 1/4, NW. 1/4 SW. 1/4, NE. 1/4 SW. 1/4, and NW. 1/4 Se. 1/4 section 16, all in township 5 south, range 8 east, Gila and Salt river meridian, Arizona, containing 480 acres more or less, and including the Casa Grande ruin, be reserved in accordance with the authority vested in you by the act of March 2, 1889 (25 Stat., 961), for the protection of the ruin.

  The Director of the Bureau of Ethnology requests that the
  reservation be made, and the Acting Commissioner of the General Land
  Office knows of no objection to such action.