FEWKES] EXCAVATIONS AT CASA GRANDE, ARIZONA 293 



roofs, drift sand, and other accumulations. In places the former 

 height of the walls has undoubtedly been reduced several feet by 

 portions falling down, and the earth about their foundations has 

 gradually been raised to a level with their tops. 



Some excavations were made in mounds of the fourth and fifth 

 classes to determine their structure, but most of the time was devoted 

 to the most important, or those containing rooms, as this seemed the 

 best use to make of an appropriation allotted for excavation, preser- 

 vation, and repair of the ruin. The work was largely devoted to 

 one of the first class. 



COMPOUNDS 



The first class of mounds, consisting of those called compounds, 

 is the most important of the above-mentioned divisions of mounds 

 in the Casa Grande group, and is typical of the Gila Valley. Since 

 the word compound 1 is here formally introduced to archeologists as 

 the name of a new type of prehistoric structures of the Southwest, it 

 may be well to dwell in detail on some of the salient features of the 

 structure thus designated. 



The compound is the characteristic structure of .the Gila and Salt 

 River valleys, as the pueblo is the type of the Little Colorado and 

 Rio Grande drainage areas. The name is applied to a rectangular 

 area bounded by a wall enclosing rooms, some of which are joined 

 to the surrounding wall, while others are independent of it. A com- 

 pound recalls Mexican rather than Puebloan architecture, although 

 it has features in common with the latter. The compound was some- 

 thing more than a building for habitation; it was a gathering place 

 for a much larger population than could be domiciled within it, and 

 was apparently for assemblages both sacred and secular, for cere- 

 monies, trade, protection from foes, and storage of food. The en- 

 closed houses are comparable to composite kivas or ceremonial 

 rooms. While the shape of a compound is, approximately, rectangu- 

 lar, it is not perfectly so, as no two sides have the same length and 

 no angles are right angles ; nor is the ground plan of any room ex- 

 actly rectangular. This imperfection is believed not to have been a 

 matter of design, but rather the result of a lack of instruments for 

 precise measurement. A compound shows a preconceived plan of 

 construction in contrast with a pueblo, to which additions were made 

 as necessity required. Its ultimate form was apparently thought out 



1 From the Malay kampong, according to the Standard Dictionary. 



