Chapter 2

About the center of the eastern side of the terrace, and also on the western side, the water which falls on the surface of the structure is discharged through rather pronounced depressions at these points. These depressions are not the work of running water, though doubtless emphasized by that agency, but represent low or open spaces in the original structure, probably passageways or gateways. Furthermore, before or inside each gateway there is a slightly depressed area, just where we would expect to find it under our hypothesis, and showing that the process of filling in is not yet completed. If the structure were to remain undisturbed for some decades longer these spaces would doubtless be filled up from material washed from the mounds, giving eventually a continuous slope from the base of the mounds to the edge of the terrace.

On the eastern margin of the map and in the southeastern corner two small and sharply defined mounds, differing in character from any others of the group, are represented. That shown on the eastern margin rises about 6 feet and the other about 10 feet above the surrounding level, and both stand out alone, no other remains occurring within a hundred yards in any direction. These mounds seem a thing apart from the other remains in the group; and it is probable that they represent the latest period in the occupancy of this site, or possibly a period subsequent to its final abandonment as a place of residence. Analogous remains occur in conjunction with some large ruins in the north, and there they represent single rooms, parts of the original structure kept in a fair state of preservation by occasional repairs while the remainder of the village was going to ruin, and used as farming outlooks long after the site was abandoned as a place of residence. As these farming outlooks have been discussed at some length in another paper[1] it is not necessary here to enlarge upon their function and the important part they play in Pueblo architecture. If the high mounds in question mark, as supposed, the sites of farming outlooks such as those which are found in the north, they indicate that the occupancy of the region in which they occur was continued after the abandonment of the Casa Grande structure by the people who built it or by people of similar habits and customs.

[Footnote 1: A Study of Pueblo Architecture; 8th Ann. Rep. Bur. Eth., 1891, pp. 86, 227, and elsewhere.]

An inspection of the map will show a number of depressions, some of quite large area, indicated by dotted contour lines. The principal one occurs a little west of the center of the area, and is worth more than a passing notice since similar structures are widely distributed throughout this region. It may be roughly characterized as a mound with excavated center. The ground for some distance about the structure (except for two depressions discussed later) is quite flat. From this flat surface as a base the structure rises to a height of 5 feet. From the exterior it has the appearance of an ordinary mound, but on reaching the top the interior is found to be hollowed out to a depth which even at the present day is below the surrounding surface, although not below the depressions adjoining. The main structure or mound is shown in figure 329 (an enlargement from the map). It measures on top of the crest 150 feet from north to south and about 80 feet from east to west, but covers a ground area of 200 feet by 120 feet or over half an acre. The crest is of the same height throughout, except for slight elevations on the eastern and western sides and a little knoll or swell in the southwestern corner. There is no indication of any break in the continuity of the crest such as would be found were there openings or gateways to the interior. The bottom of the depression in the main structure is at present about a foot below the surrounding ground surface, but it must have been originally considerably more than this, as the profile indicates long exposure to atmospheric erosion and consequent filling of the interior. No excavation was made and the character of the construction can not be determined, but the mound is apparently a simple earth structure--not laid up in blocks, like the Casa Grande ruin.

To the east and to the west are two large depressions, each about 5 feet below the surrounding ground surface, evidently the places whence the material for the construction of the mound was obtained. Yet the amount of material removed from these excavations must have been considerably in excess of that used in the construction of the mound, and this excess was doubtless utilized in neighboring constructions, since it is hardly to be supposed that it was carried away to any considerable distance.

The purpose of this hollow mound, which is a fair type of many similar structures found in this region, is not clear. Mr. Frank Hamilton Cushing, while director of the Hemenway southwestern archeological expedition, found a number of these structures and excavated some of them. From remains thus found he concluded that they were sun-temples, as he termed them, and that they were covered with a roof made of coiled strands of grass, after a manner analogous to that in which pueblo baskets are made. A somewhat similar class of structures was found by the writer on the upper Rio Verde, but these were probably thrashing floors. Possibly the structure under discussion was for a similar purpose, yet its depth in proportion to its size was almost too great for such use. The question must be left for determination if possible by excavation.

In the southern central part of the map is shown another excavation, covering a larger area than any of the others, of very irregular outline and from 3 to 4 feet deep. It is apparently older than the others and probably furnished the material for the house structures northeast and southwest of it. Bordering the depression on the south there are some low mounds, almost obliterated, which probably were the sites of other house structures.

Scattered about the area shown on the map there are several small depressions, usually more regular in outline than those described. The best example is situated near the northeastern corner of the area. It is situated in the point of a low promontory, is about 3 feet deep, almost regularly oval in outline, and measures about 50 by 100 feet. A similar depression less than 2 feet deep occurs near the northwest corner of the area, and immediately south of the last there is another, more irregular in outline, and nearly 3 feet deep. There are also some small depressions in the immediate vicinity of the Casa Grande ruin and of the mounds north of it.

With a single exception none of these depressions are so situated that they could be used as reservoirs for the storage of water collected from the surface, and the catchment area of the depressions is so small and the rate of evaporation in this area so great that their use as reservoirs is out of the question. It is probable that all of the smaller depressions represent simply sites where building material was obtained. Possibly the ground at these points furnished more suitable material than elsewhere, and, if so, the builders may have taken the trouble to transport it several hundred yards rather than follow the usual practice of using material within a few feet of the site. This hypothesis would explain the large size of the depressions, otherwise an anomalous feature.

CASA GRANDE RUIN.

_State of Preservation._

The area occupied by the Casa Grande ruin is insignificant as compared with that of the entire group, yet it has attracted the greater attention because it comprises practically all the walls still standing. There is only one small fragment of wall east of the main structure and another south of it.

The ruin is especially interesting because it is the best preserved example now remaining of a type of structure which, there is reason to believe, was widely distributed throughout the Gila valley, and which, so far as now known, is not found elsewhere. The conditions under which pueblo architecture developed in the north were peculiar, and stamped themselves indelibly on the house structures there found. Here in the south there is a radical change in physical environment: even the available building material was different, and while it is probable that a systematic investigation of this field will show essentially the same ideas that in the north are worked out in stone, here embodied in a different material and doubtless somewhat modified to suit the changed environment, yet any general conclusion based on the study of a single ruin would be unsafe. In the present state of knowledge of this field it is not advisable to attempt more than a detailed description, embodying, however, a few inferences, applicable to this ruin only, which seem well supported by the evidence obtained.

The Casa Grande ruin is located near the southwestern corner of the group, and the ground surface for miles about it in every direction is so flat that from the summit of the walls an immense stretch of country is brought under view. On the east is the broad valley of Gila river rising in a great plain to a distant range of mountains. About a mile and a half toward the north a fringe of cottonwood trees marks the course of the river, beyond which the plain continues, broken somewhat by hills and buttes, until the view is closed by the Superstition mountains. On the northwest the valley of Gila river runs into the horizon, with a few buttes here and there. On the west lies a range of mountains closing the valley in that direction, while toward the southwest and south it extends until in places it meets the horizon, while in other places it is closed by ranges of mountain blue and misty in the distance. In an experience of some years among northern ruins, many of them located with special reference to outlook over tillable lands, the writer has found no other ruin so well situated as this.

The character of the site occupied by the ruin indicates that it belongs to a late date if not to the final period in the occupancy of this region, a period when by reason of natural increase of numbers, or perhaps aggregation of related gentes, the defense motive no longer dominated the selection of a village site, but reliance was placed on numbers and character of structures, and the builders felt free to select a site with reference only to their wants as a horticultural people. This period or stage has been reached by many of the Pueblo tribes, although mostly within the historical period; but some of them, the Tusayan for example, are still in a prior stage.

A ground plan of the ruin is shown in plate LII, and a general view in plate LIII. The area covered and inclosed by standing walls is about 43 feet by 59 feet, but the building is not exactly rectangular, and the common statement that it faces the cardinal points is erroneous. The variation from the magnetic north is shown on the ground plan, which was made in December, 1890. The building comprised three central rooms, each approximately 10 by 24 feet, arranged side by side with the longer axes north and south, and two other rooms, each about 9 by 35 feet, occupying respectively the northern and southern ends of the building, and arranged transversely across the ends of the central rooms, with the longer axes running east and west. Except the central room, which was three stories in height, all the rooms were two stories above the ground. The northeastern and southeastern corners of the structure have fallen, and large blocks of the material of which they were composed are strewn upon the ground in the vicinity. It is probable that the destruction of these corners prior to that of the rest of the building was due to the disintegration of minor walls connected with them and extending, as shown by the ridges on the ground plan, northward from the northeastern corner and eastward from the southeastern corner. These walls doubtless formed part of the original structure and were probably erected with it; otherwise the corners of the main structure would not have been torn out or strained enough to fall before the rest of the building was affected.

It is not likely that the main building originally stood alone as at present. On the contrary there is every reason to suppose that it was connected with other buildings about 75 feet east of it, now marked by a bit of standing wall shown on the map (plate LI), and probably also with a small structure about 170 feet south of it, shown in plate LIV. These connections seem to have been by open courts inclosed by walls and not by continuous buildings. The court east of the ruin is well marked by the contours and seems to have been entered by a gateway or opening at its southeastern corner.

_Dimensions._

It is probable that the area immediately adjacent to the ruin, and now covered by mounds, carried buildings of the same time with the main structure and was occupied contemporaneously with it or nearly so. This area, well marked on the map, measures about 400 feet north and south, and 240 feet east and west. It is not rectangular, although the eastern and western sides, now marked by long ridges, are roughly parallel. The northeastern corner does not conform to a rectangular plan, and the southern side is not more than half closed by the low ridge which extends partly across it. This area is doubtless the one measured in 1776, by Padre Font, whose description, was copied by later writers, and whose measurements were applied by Humboldt and others to the ruin itself. Font gave his measurements as those of a circumscribing wall, and his inference has been adopted by many, in fact most, later writers. A circumscribing wall is an anomalous feature, in the experience of the writer, and a close inspection of the general map will show that Font's inference is hardly justified by the condition of the remains today. It seems more likely that the area in question was covered by groups of buildings and rows of rooms, connected by open courts, and forming an outline sometimes regular for a considerable distance, but more often irregular, after the manner of pueblo structures today. The long north and south ridge which forms the southeastern corner of the area, with other ridges extending westward, is quite wide on top, wide enough to accommodate a single row of rooms of the same width as those of the ruin, and it is hardly reasonable to suppose that a wall would be built 10 or 12 feet wide when one of 4 feet would serve every purpose to which it could possibly be put. Furthermore, the supposition of an inclosing wall does not leave any reasonable explanation of the transverse ridges above mentioned, nor of the long ridge which runs southward from the southeastern corner of the ruin.

The exterior walls rise to a height of from 20 to 25 feet above the ground. This height accommodated two stories, but the top of the wall is now 1 to 2 feet higher than the roof level of the second story. The middle room or space was built up three stories high and the walls are now 28 to 30 feet above the ground level. The tops of the walls, while rough and much eroded, are approximately level. The exterior surface of the walls is rough, as shown in the illustrations, but the interior walls of the rooms are finished with a remarkable degree of smoothness, so much so as to attract the attention of everyone who has visited the ruin. Mange, who saw the ruin with Padre Font in 1697, says the walls shine like Puebla pottery, and they still retain this finish wherever the surface has not cracked off. This fine finish is shown in a number of illustrations herewith. The walls are not of even thickness. At the ground level the exterior wall is from 3½ to 4½ feet thick, and in one place at the southern end of the eastern wall, is a trifle over 5 feet thick. The interior walls are from 3 to 4 feet thick at base. At the top the walls are reduced to about 2 feet thick, partly by setbacks or steps at the floor levels, partly by exterior batter, the interior wall surface being approximately vertical. Some writers, noting the inclination of the outer wall surface, and not seeing the interior, have inferred that the walls leaned considerably away from the perpendicular. This inference has been strengthened, in some cases, by an examination of the interior, for the inner wall surface, while finely finished, is not by any means a plane surface, being generally concave in each room; yet a line drawn from floor level to floor level would be very nearly vertical. The building was constructed by crude methods, thoroughly aboriginal in character, and there is no uniformity in its measurements. The walls, even in the same room, are not of even thickness, the floor joists were seldom on a straight line, and measurements made at similar places, e.g., the two ends of a room, seldom agree.

A series of precise measurements gives the following results: Outside eastern wall, at level 3 feet above center of depressed area adjoining the ruin on the east, 59 feet; western wall at same level, 59 feet 1 inch; northern and southern walls, at same level, 42 and 43 feet respectively. These measurements are between points formed by the intersection of the wall lines; the northeastern and southeastern corners having fallen, the actual length of standing wall is less. At the level stated the northern wall measures but 34 feet 4 inches, and the southern wall 36 feet 10 inches. A similar irregularity is found in the interior measurements of rooms. The middle room is marked by an exceptional departure from regularity in shape and dimensions. Both the east and west walls are bowed eastward, making the western wall convex and the eastern wall concave in reference to the room.

Precise measurements of the middle room at the second floor level, 8 feet above the base previously stated, are as follows: Eastern side, 24 feet 8½ inches; western side, 24 feet 2 inches; northern side, 9 feet 3½ inches; southern side, 9 feet 1 inch. The eastern room is a little more regular, but there is a difference of 11 inches between the measurements of the northern and southern ends. A similar difference is found in the western room, amounting there to 6 inches. The northern and southern rooms do not afford as good bases for comparison, as a corner is missing in each; but measurements to a point where the interior wall surfaces would intersect if prolonged, show variations of from 6 inches to a foot. The statement that the ruin exhibits exceptional skill in construction on the part of the builders, is not, therefore, supported by facts.

_Detailed Description._

The Casa Grande ruin is often referred to as an adobe structure. Adobe construction, if we limit the word to its proper meaning, consists of the use of molded brick, dried in the sun but not baked. Adobe, as thus defined, is very largely used throughout the southwest, more than nine out of ten houses erected by the Mexican population and many of those erected by the Pueblo Indians being so constructed; but, in the experience of the writer, it is never found in the older ruins, although seen to a limited extent in ruins known to belong to a period subsequent to the Spanish conquest. Its discovery, therefore, in the Casa Grande would be important; but no trace of it can be found. The walls are composed of huge blocks of earth, 3 to 5 feet long, 2 feet high, and 3 to 4 feet thick. These blocks were not molded and placed in situ, but were manufactured in place. The method adopted was probably the erection of a framework of canes or light poles, woven with reeds or grass, forming two parallel surfaces or planes, some 3 or 4 feet apart and about 5 feet long. Into this open box or trough was rammed clayey earth obtained from the immediate vicinity and mixed with water to a heavy paste. When the mass was sufficiently dry, the framework was moved along the wall and the operation repeated. This is the typical pisé or rammed-earth construction, and in the hands of skilled workmen it suffices for the construction of quite elaborate buildings. As here used, however, the appliances were rude and the workmen unskilled. An inspection of the illustrations herewith, especially of plate LV, showing the western wall of the ruin, will indicate clearly how this work was done. The horizontal lines, marking what may be called courses, are very well defined, and, while the vertical joints are not apparent in the illustration, a close inspection of the wall itself shows them. It will be noticed that the builders were unable to keep straight courses, and that occasional thin courses were put in to bring the wall up to a general level. This is even more noticeable in other parts of the ruin. It is probable that as the walls rose the exterior surface was smoothed with the hand or with some suitable implement, but it was not carefully finished like the interior, nor was it treated like the latter with a specially prepared material. The material employed for the walls was admirably suited for the purpose, being when dry almost as hard as sandstone and practically indestructible. The manner in which such walls disintegrate under atmospheric influences has already been set forth in detail in this report. An inhabited structure with walls like these would last indefinitely, provided occupancy continued and a few slight repairs, which would accompany occupancy, were made at the conclusion of each rainy season. When abandoned, however, sapping at the ground level would commence, and would in time level all the walls; yet in the two centuries which have elapsed since Padre Kino's visit--and the Casa Grande was then a ruin--there has been but little destruction, the damage done by relic hunters in the last twenty years being in fact much greater than that wrought by the elements in the preceding two centuries. The relic hunters seem to have had a craze for wood, as the lintels of openings and even the stumps of floor joists have been torn out and carried away. The writer has been reliably informed that as late as twenty years ago a portion of the floor or roof in one of the rooms was still in place, but at the present day nothing is left of the floors except marks on the vertical walls, and a few stumps of floor joists, deeply imbedded in the walls, and so high that they can not be seen from the ground.

The floors of the rooms, which were also the roofs of the rooms below, were of the ordinary pueblo type, employed also today by the American and Mexican population of this region. In the Casa Grande ruin a series of light joists or heavy poles was laid across the shorter axis of the room at the time the walls were erected; these poles were 3 to 6 inches in diameter, not selected or laid with unusual care, as the holes in the side walls which mark the places they occupied are seldom in a straight line, and their shape often indicates that the poles were quite crooked. Better executed examples of the same construction are often found in northern ruins. Over the primary series of joists was placed a layer of light poles, 1½ to 2 inches in diameter, and over these reeds and coarse grass were spread. The prints of the light poles can still be seen on the walls. The floor or roof was then finished with a heavy coating of clay, trodden down solid and smoothed to a level. A number of blocks of this final floor finish, bearing the impress of the grass and reeds, were found in the middle room. There is usually a setback in the wall at the floor level, but this practice was not followed in all the rooms.