MiNDELEFF] FURTHER EXAMINATION RECOMMENDED 345 



provision be made for further protectiug Casa Graude ruin, near Flor- 

 ence, Arizona, by the erection of a suitable roof, has been under con- 

 sideration. 



In many respects Casa Grande ruin is one of the most noteworthy 

 relics of a prehistoric age and people remaining within the limits of the 

 United States. It was discovered, already in a ruinous condition, by 

 Padre Kino in 1G94, and since that time it has been a subject of record 

 by explorers and historians. Thus its history is exceptionally extended 

 and complete. By reason of its early discovery and its condition when 

 first seen by white men, it is known that Casa Graude is a strictly 

 aboriginal structure; and archeologic researches in this country and 

 Mexico afford grounds for considering it a typical structure for its times 

 and for the natives of the southwestern region. Mauy other structures 

 were mentioned or described by the Spanish explorers, but the impres- 

 sions of these explorers were tinctured by previous experience in an 

 inhospitable region, and their descriptions were tinged by the romantic 

 ideas of the age; very few of tliese structures were within the limits 

 of the I'nited States, and nearly all of these situated in the neighboring 

 republic of Mexico disappeared long ago; there is hardly a structure 

 lei't, except Casa Grande ruin, by which the early accounts of Siianish 

 explorers in Xorth America can be checked and interpreted — none 

 other of its class exists in the ITnited States. Casa Grande ruin is, 

 therefore, a relic of exceptional importance and of essentially uiii(|ne 

 character. 



Unfortunately this structure, like others erected by the most advanced 

 among the native races in the southwest, is of perishable material; it 

 is built of adobe, or rather of cajon, i. e., of a puddled clay, molded into 

 walls, dried in the sun. Such walls would stand a short time only in 

 humid regions; but in the arid region the material is desiccated and 

 baked under cloudless sky and sun for many months at a time, and 

 becomes so hard as to resist, fairly, the rare storms of the region. It is 

 by reason of climatal conditions that cajon and adobe have come into 

 general use for building in southwestern United States, as in contigu- 

 ous parts of Mexico; and it is by reason of the same conditions that a 

 few of the ancient structures remain, and the best preserved of all is 

 found in the Gila valley, one of the most desert regions on the westerii 

 hemisphere. Yet the best of the cajon structures is perishable; so long 

 as the roof remains and the summits of the walls are protected, disin- 

 tegration proceeds slowly; but when the projecting roof is removed, 

 the rare but violent storms attack the walls, and they are gradually 

 channeled aud gullied by the storm waters, while the exterior surface 

 gradually disintegrates and falls away under the alternate wetting and 

 drying. Even in the most arid regions, the earth-built structures typ- 

 ical of the southwest are surely, albeit slowly, ravaged and destroyed. 



Several years ago Casa Grande ruin was brought into general jiotice 

 throughout the United States in consequence of southwestern explora- 



