Site 418 (Figure **)

Site 418 is located ca. 0.8km southeast of Site 426 and 0.5km southwest of Site 423 on the far southern edge of the Naco valley. The closest perennial stream, the Quebrada Agua Sucia, is ca. 700m to the south whereas a tributary of the currently seasonal Quebrada Agua Sucia lies 150m to the north. Site 418 consists of five low constructions organized around a central plaza. The land surrounding the settlement slopes up very gradually from north-to-south towards the foothills the steep base of which is approximately 200m to the south. Roughly 77m2 was excavated here from February 28-March20, 1992 in the course of investigating Strs. 418-2 and 418-5. These investigations were directed by Neil Ross, assisted near the work’s conclusion by L. True.

Structure 418-2 (Figures **-**)

Structure 418-2, the largest building recorded at Site 418, closes off the west side of the central patio. It is 8.5m southwest of Str. 418-5 and **m west, and across the patio from, Str. 418-4. Excavations conducted here within Subop. 418B and E uncovered ca. 41m2 in the course of revealing about two-thirds of the edifice. Digging was pursued to maximum depths of 0.6m and 0.93m below modern ground surface within and beyond construction, respectively. One major building episode was identified in the course of this work, directed by N. Ross.

Time Span	Construction Phase	Units	Strata	Features	Date
1	-	-	S.4,5	-
2	Str. 418-2-Sub1	U.1,2	-	F.3	LCLII?
3	-	-	S.3	-	LCLII?
4	Str. 418-2-1st	U.1-11,15,18	-	-	LCLII
5	Str. 418-2-1st	U.12,14,16,17,19,20	-	F.2,4	LCLII,III
6	-	-	S.1-3	F.1

Time Span 1

The earliest activity attested to in Str. 418-2-1st’s vicinity is the apparent natural deposition of a very coarse-textured strong to yellow-brown sand (S.5). Stratum 5 was revealed in a deep probe sunk off Str. 418-2's north side where it was found to be at least 0.18m thick (S.5's base lay beyond excavation limits). The upper surface of S.5 runs flat for the 1m it was exposed.

Overlying S.5 by 0.13-0.2m is a hard-compacted, very coarse-textured, black soil containing small fragments of metamorphic rocks (S.4). Stratum 4 rises 0.07m over the 1m it was uncovered running south-to-north. This ascent occurs in one steep step, a shift that may have been due to human modifications of the area during TS. 2.

No artifacts are clearly associated with these levels, implying at best a sparse human presence in the immediate area while S.4 and 5 were accumulating.

Time Span 2

Two, most likely distinct, structures were seemingly erected during this interval. The most substantial of these is Str. 418-2-Sub1 which is located below and 1m east of Str. 418-2-1st’s east basal facing (U.3). Excavation in this area revealed the northwest corner of what may have been a surface-level building whose foundations were ca. 0.15m high. Only 0.5m of the north footing (U.1) and 0.7m of its western analogue (U.2) were uncovered; the building’s estimated orientation is 28 degrees. The surviving tops of U.1 and 2 are equivalent to the base of U.3. Units 1 and 2 are fashioned of faced tuff blocks set in a mud mortar.

Roughly 5.5m northwest of Str. 418-2-Sub1 is what appears to be a posthole (F.3) sunk into S.4 and 5. Feature 3 is 0.18m wide by 0.24m deep, narrowing from its top to a rounded base. The earthen surface into which F.3 was dug is 0.07m lower on the south than it is on the north. As noted earlier, this discrepancy may be due to a natural rise in the ancient ground level or to human modification of the existing terrain. In the latter case, the floor of whatever space the F.3 posthole delimited may have been sunk slightly (0.07m to be exact) below ground surface.

Time Span 2, therefore, witnesses the first clear human occupation within Str. 418-2's vicinity. Specifically, at least two surface-level buildings were raised here, one delimited by stone foundations that supported perishable upper walls, the other possibly bounded by walls raised without benefit of rock footings.

Time Span 3

Structure 418-2-Sub1 and F.3 were subsequently blanketed by as much as 0.2m of a very hard-compacted, grayish brown loam containing small specks of metamorphic rocks (S.3). Artifacts recovered from S.3 point to continued human use of the immediate area while this soil was being laid down. It is unclear whether S.3 was deposited by natural means or was introduced to level out the area prior to erecting Str. 418-2-1st. That S.3 continued to accumulate after the platform was abandoned implies that this layer was the result of natural sedimentation in both TS. 3 and 5.

Time Span 4

Structure 418-2-1st was, during this span, a platform bounded on all sides by stone facings (U.1-4). The east and west sides are defined by steep ascents directly to the summit. The northern flank is ascended by two stone-faced terraces (U.5 and 6) that rise above the northern basal wall (U.1). Unit 1 ascends 0.2m above ancient ground surface and runs back (south) for 0.45m where it is succeeded by U.5. The latter is 0.1m high and measures 0.56m across. Unit 6 then stands 0.3m above U.5's tread and gives way to a stone pavement (U.12) that extends 2.19m south across the summit. Units 1, 5, and 6 apparently run the full length of Str. 418-2-1st’s north flank and served as broad steps leading to the building’s superstructure. The situation on the south is less clear. Here, U.4 may have originally risen 0.5m to the summit. Constructions appended to this flank during TS. 5, however, may well have obscured earlier terraces. At present, therefore, it looks like Str. 418-2-1st faced north during TS. 4, its superstructure being entered from that side. We cannot rule out the possibility, however, that the south side was also terraced and provided another means of access to the summit.

The limited portion of the fill contained by U.1-4 that we sampled consists of a hard-compacted, coarse-textured, very dark gray-brown to black soil in which a few small cobbles are embedded (U.15).

The superstructure consists of five rooms: three set in an east-west line along the summit’s southern margin (Rooms 1-3) and two on its north side (Rooms 4 and 5). A large stone-faced and -surfaced bench (U.9), standing 0.35m high and covering 1.13m north-south by an estimated 4.8m east-west, separates the two set of compartments. The southern enclosures are floored with earth. The larger eastern (Room 1, 1.2x1.8m) and western (Room 2, 1.1x1.85m) flank a smaller, central cubicle (Room 3, 1.14x1.2m). None of these enclosures contains built-in furniture though they are all bordered by the U.9 bench on the north. Room 4, the largest in the superstructure, measures 2.19x3.18m and is paved with stones. Immediately to its east, Room 5 measures 1x2.19m. Room 5's floor, likely consisted of earth. This putative surface is 0.56m above a pavement of small cobbles and schist slabs (U.18) that runs up to, but not under, U.7 and 9 which border Room 5 on the west and south, respectively. Unit 18, in fact, is at approximately the same level as the ground surface above which Str. 418-2-1st was raised. Most likely, U.18 was part of an earlier version of Str. 418-2-1st, probably part of a surface-level room delimited by U.7, 9, and, possibly, U.3 and 6. If this was the case, then Str. 418-2-1st may have started out as a ground-level building that was later converted into a platform.

By the conclusion of TS. 4, Str. 418-2-1st was a 0.5-0.6m high, stone-faced, earth-and-stone-filled platform that measured 4.95x5.89m, and was aligned approximately 24 degrees. The superstructure was apparently reached by ascending three low stone-faced risers that run the full width of the platform’s north face. These led to a superstructure composed of five rooms. The largest of these, Room 4, covers 6.7m2, is paved with stones, and is open on the north where it overlooks the aforementioned steps. Bordering Room 4 on the east is an earthen-floored compartment covering 2.19m2 (Room 5). Bordering Rooms 4 and 5 on the south is a large stone-faced and -surfaced bench that is 0.35m high, 1.13m wide, and seemingly runs the full width of the summit (an estimated 4.8m east-west). Backing this bench on the south are three small, earthen-floored cubicles arranged in an east-west line. The diminutive central compartment encompasses 1.4m2 and is flanked by two slightly larger spaces, measuring 2.2m2 and 2m2 on the west and east, respectively. Time Span 4 constructions are generally fashioned of angular stones, mostly tuff, with their flatter faces oriented outwards. The principal exceptions to this trend are U.5 and 7. Unit 5, the second ascending riser in the northern terrace triad, consists of an upper course composed of cut blocks and two schist slabs which is underlain by additional slabs and chinking stones. Unit 7, the footing dividing Rooms 4 and 5, is capped by faced tuff slabs which are, in turn, supported by un-coursed medium-size angular rocks and smaller chinking stones. One cut block appears at the junction of U.1 and 2, the platform’s northwest corner. All of the rocks are set in a mud mortar.

The discovery of a stone floor underlying Room 4's surface by 0.56m suggests the possibility that the building began its use-life as a surface-level edifice. Subsequent filling of its interior space with earth and a few small stones would have converted said structure into the platform described above.

Time Span 5

During this interval, Str. 418-2-1st retained its basic form, dimensions, and orientation. The major changes involved additions made to the platform’s north and south sides. In the latter direction, three roughly parallel lines of stones set on end were raised now (U.13, 14, and 17). Unit 14, the southern-most of these constructions, is 0.46m wide and was exposed for 3.85m running at an alignment of 292 degrees. The unit’s western edge was not definitively identified though it stops on the east without intersecting with any known architecture. Unit 13, 0.19m north of U.14, measures 0.43m across and was followed 2.5m west from its eastern junction with U.16. The latter is a low stone construction that runs 0.7m north from U.13's south face to where it intersects U.17's south flank. Unit 17, in turn, is 0.43m north of U.13, 0.17m wide, and was revealed for only 1m running east-west. A stone pavement (included in U.13) fills the intervening space between U.13 and U.17; a comparable surface (included in U.17) may also have extended the 0.31m between U.17 and U.4, Str.418-2-1st’s southern basal wall. No comparable pavement was noted filling the gap between U.14 and 13. In addition to these relatively clear constructions, remnants of what may have been two additional lines of rocks set vertically were recorded 0.16m and 0.78m south of U.14 (F.4 and 2, respectively). Features 2 and 4 are potential rock walls 0.42m and 0.35m across; no pavements link them to adjoining architecture and they were not well enough preserved to trace out to the east and west. Units 13, 14, 17, and F. 2 and 4 are 0.2-0.35m high.

The architectural significance of these southern additions is unclear. Given the pavements linking them, U.13 and 17 may have been terraces appended to Str. 418-2-1st’s south flank. If so, they would have enlarged the building by 1.35m in this direction, creating two stone-faced risers that ascended 0.26m and 0.35m towards the summit from south to north. Unit 4, the platform’s southern basal facing, would still have projected 0.1m above the U.17 tread. Unit 14's erection buries all but the upper-most 0.04m of U.13 and is not linked to the latter be a formalized terrace tread. Rather, the 0.19m separating these units is filled a hard-compacted, coarse-textured, dark grayish brown to black soil in which numerous small and medium-size rocks are embedded (U.19). It may be that U.14 was added late in Str. 418-2-1st’s use-life to replace U.13, creating a basal southern terrace that was 1.52m wide (extending north to U.17). Features 2 and 4, if they actually are the remains of walls, might have been parts of subsequent, very casually built, extensions of the basal southern terrace. The primary problem with this scenario is that, whereas U.16 may be the eastern terminus of U.13, there are no other indicators of how the supposed terraces related to the larger construction from which they presumably projected. Unit 14, in fact, simply stops on the east and does not run back to Str. 418-2-1st’s core platform. It may be, therefore, that the southern additions are not all terraces. Units 13 and 17 are the most likely candidates for having served this function whereas U.14 and F.2 and 4 may simply have been stone lines unrelated to any effort to extend Str. 418-2-1st southward.

The only modification recognized on the north is the construction of a 0.3m high by 0.2m wide stone wall (U.20) that projects at least 1m north from its abutment with U.1 (Str. 418-2-1st’s northern basal wall; U.20's north end was not uncovered). Given the relative narrowness of this wall, it seems likely that U.20 was a foundation from a surface-level construction appended to the platform’s north face.

By the conclusion of TS. 5, Str. 418-2-1st may well have measured 4.95x7.24m and been ascended by two stone-faced and -surfaced terraces on the south leading to a 0.1m-high step-up to the summit (the surviving top of U.4). Both the north and south faces would, therefore, have been mounted by three risers. Otherwise, the building’s dimensions, basic orientation, and arrangement of spaces within the superstructure remained unchanged. Additional architecture on the north and south may have been parts of surface-level constructions raised late in the site’s occupation sequence. Units 13, 14, 17, and F. 1 and 2 are built of cobbles and angular tuff rocks set on end. Unit 20 and the surfaces backing U.13 and 17 consist of the same mix of rocks laid horizontally. All of the TS. 5 architecture is set in a mud mortar.

Time Span 6

Following Str. 418-2-1st’s abandonment, S.3 resumed accumulating, eventually covering all but the top-most of U.1 and 20 on the north; this soil apparently did not continue to collect on the south during TS. 6. Blanketing S.3 by 0.09-0.22m is a hard-compacted, coarse-textured, dark grayish brown to black soil (S.2). Stratum 2, in turn, is covered by 0.12-0.21m of a hard-compacted, root-rich, dark grayish brown loam (S.1). Included in S.1 and 2 is a moderate to light concentration of rocks that fell from Str. 418-2-1st’s final-phase construction (F.1). Feature 1 is densest where it overlies architecture and drops off rapidly off the building’s flanks.

Structure 418-5 (Figures **-**).

Structure 418-5 is located on the plaza’s north side, 8.5m northeast of Str. 418-2 and **m north and across the patio from Str. 418-1. Excavations conducted within Subop. 418C and D revealed all but the building’s northwest corner in the course of uncovering ca. 36m2. Digging was pursued to maximum depths of 0.58m and 0.64m below modern ground surface within and beyond construction, respectively. One major building phase was identified in the course of these investigations overseen by N. Ross.

Time Span	Construction Phase	Units	Strata	Features	Date
1	-	-	S.3-5	-	LPrecl,LCLI
2	Str. 418-5-1st	U.1-8,10,13,15	-	-	LCLII
3	Str. 418-5-1st	U.9,11,12,14	-	-	LCLII/III,III
4	-	-	S.1,2	F.1

Time Span 1

The earliest recorded activity attested to in Str. 418-5-1st’s vicinity is the seemingly natural deposition of S.4 and 5. The latter, a hard-compacted, coarse-textured, very dark grayish brown loam with chunks of small metamorphic rocks, was exposed to a maximum thickness of 0.07m; it base lies beyond excavation limits. Stratum 5 was uncovered only off the platform’s west side where it runs relatively flat over the 1.07m it was exposed extending east-west. Stratum 4 resembles S.5 in hardness and color but is a fine-textured, silty loam. Only 0.02m of this layer was revealed, this time at the base of a probe dug into Str. 418-5-1st’s summit; once more, the stratum’s base eluded detection beyond excavation limits. Stratum 4 was found to run flat over the 0.52m it was uncovered extending east-west. No artifacts are clearly derived from either S. 4 or 5, tentatively hinting at the absence of a human occupation in the area while these soils were being laid down.

Stratum 3, a hard-compacted, moderately fine-textured, grayish brown soil with small inclusions of metamorphic rocks, blankets S.5 by 0.2-0.24m. This soil layer ascends 0.25m over the 12.16m it was exposed from east to west. All TS. 2 construction is set into or on S.3, indicating that its upper surface served as ground level during the platform’s occupation. Artifacts retrieved from S.3 indicate a human presence in the area when this soil was accumulating.

Time Span 2

The first version of Str. 418-5-1st that we can identify consists of a low platform bounded on all sides by stone facings (U.1-4). The earthen-floored summit consists of two rooms divided by low (0.19-0.3m tall) stone foundations measuring 0.25-0.35m across (U.6-8). The largest of these compartments is L-shaped; its wide stem takes up all of the northern summit, covering 1.7x3m whereas its shorter stem projects 1.2m south along the superstructure’s east side, encompassing 1.1m across east-west. The remaining cubicle occupies the summit’s southwest corner where it measures 0.95x1.1m. This latter space is delimited by stone foundations on the north, east, and west (U.6, 8, and 7) while U.4, the southern basal wall, closes off the south side. Narrow gaps breach the room’s southwest (0.2m wide) and northeast corners (0.25m across). Too narrow to have been doors, these fissures may have provided ventilation, drawing air across the room from northeast to southwest or vice versa. A 0.2m wide (east-west) by 1m long space intervenes between the southwest compartment and the western summit edge; the architectural and behavioral significance of this space, if any, is unclear.

Though the low basal facings unlikely posed serious obstacles to reaching the summit, two sets of stone steps were built against the edifice’s west side and northeast corner. The more formal of the pair, U.5, consists of two stone risers that each stand 0.1m high and are 0.33m and 0.17m wide (ascending from the bottom to top); U.3, the west basal wall, projects an additional 0.07m above U.5's uppermost step. Unit 5 is 0.6m wide (north-south) and intersects U.3 ca. 1.2m south of the reconstructed location of Str. 418-5-1st’s northwest corner (this corner was not uncovered). These steps are roughly centered on the large, L-shaped room’s west face.

The second set of steps (U.15) is much simpler, consisting of two large rocks set side-by-side, 0.2m north of the platform’s northeast corner. Unlike U.5, U.15 is not directly connected to Str. 418-5-1st; the 0.2m separating platform and steps was apparently left open. Unit 15 stands 0.19m high and measures 0.3m on a side. It appears that U.15 was intended as a relatively informal means for accessing the superstructure’s large L-shaped room.

A stone pavement (U.10) encompassing 0.7m north-south by 1m east-west was appended to Str. 418-5-1st’s southeast corner. The limits of this construction are unclear as is its architectural and behavioral import.

The small segment of construction fill (U.13) that was sampled during excavations consists of moderately hard-compacted, coarse-textured, dark grayish-brown loam with a few included small stones.

There is some evidence that Str. 418-5-1st began its use-life as a surface-level building. There is a marked change in construction along the interior face of the eastern basal wall (U.1). The northern 1.55m of that interior facing is carefully constructed, consisting of at least three clear courses, with chinking stones packed around larger rocks that were seemingly chosen for their naturally flat faces. For 1.25m south of this point the wall steps back (east) 0.1m and is fashioned in a much more casual manner with no clear coursing of its constituent stones. It may be that there was once a 1.25m-wide doorway in Str. 418-5-1st’s southeast corner that was filled as pat of an effort to transform the construction into a low platform. This interpretation could not be proven in the field but it does make sense of the clear change in construction noted along U.1's interior.

By the conclusion of TS. 2, Str. 418-5-1st was a stone-faced, earth-filled, platform standing 0.27-0.46m high (standing taller on the east than the west), measuring 3.95x4.2m, and oriented 96 and 190 degrees. As noted above, the construction may have originally been a surface-level edifice entered through a wide (1.25m across) doorway in its southeast corner. Units 1-4 would, then, have started out as footings for perishable walls, being converted to retaining walls when the doorway was sealed and the space they defined filled with earth (U.13).

The earthen-floored summit is divided between two rooms; a large, L-shaped compartment covering 6.4m2 and a small cubicle tucked into the superstructure’s southwest corner and encompassing 1.1m2. The stone foundations that define that latter enclosure are breached by narrow (0.2-0.25m wide) passages in the cubicle’s northeast and southwest corners. These fissures may have encouraged the passage of air through the enclosed space. No built-in furniture was recorded on the summit though the 0.72m-wide eastern basal facing (U.1) could have served as a retaining wall, support for perishable upper walls, and a bench. Access to the summit was achieved by ascending a formal, albeit relatively small, staircase on the west side or by stepping on and over a more casual riser set near the platform’s northeast corner. No sign of steps leading into the patio on the south was recorded. A diminutive stone pavement measuring 0.7m2 abuts Str. 418-5-1st’s southeast corner. While the architectural significance of this surface is uncertain, it may have served as a dry work and/or storage area under the eaves of the superstructure’s roof. All TS. 2 constructions consist of a mix of river cobbles and uncut stones, mostly tuff, set in a mud mortar. Some effort was made to orient the flatter faces of these rocks outward.

Time Span 3

Structure 418-5-1st retained its basic form, dimensions, and orientation during this interval. The principal changes involved modifying the arrangement of summit rooms and the addition of an earthen-floored terrace to the platform’s east face. The latter is 0.2m-high and extends 1m east from U.3, the platform’s eastern basal wall. Structure 418-5-1st’s eastern terrace is bounded on the south (U.11) and east (U.12) by low stone walls that retain a fill composed of a moderately hard-compacted, coarse-textured, dark grayish brown loam in which are embedded numerous small to medium-size cobbles (U.14). Unit 11 intersects U.3 at a point 0.3m north of the platform’s southeast corner; the north side of the terrace was not identified in our excavations. Unit 3 still projected 0.23m above the U.11/12 terrace

The L-shaped summit room was now divided into two enclosures by the construction of U.9, a 0.12m high by 0.42m wide stone footing. Raising this north-south-running foundation converted the L-shaped room into a western compartment that measures 1.4x1.6m and an eastern enclosure covering 1.3x2.9m, the latter’s long axis running north-south. The southwest cubicle apparently remained unchanged.

During its final period of use, Str. 418-5-1st’s core platform continued to stand 0.27-0.46m high, measure 3.95x4.2m, and was aligned roughly 96 and 190 degrees. Steps still ascended the building’s west side and northeast corner and the small stone pavement built off the southeast corner remained in use. A 0.2m-high terrace now ran along the Str. 418-5-1st’s east face, extending the building 1m in this direction. The length of this addition is not known; it starts 0.3m north of the platform’s southeast corner but where it intersects U.3 on the north is uncertain. The superstructure now consists of three earthen-floored rooms; two of which are set in a north south line bounded on the east by a long enclosure. The northwest compartment covers 2.2m2 and looks out west over the U.5 steps. The southwest room is unchanged from how it appeared in TS. 2; 1.1m2 with possible ventilation holes in its northeast and southwest corners. The largest enclosure backs the previous compartments on the east and measures 3.8m2; it may have been entered by means of the U.15 step leading to the room’s northeast corner. Time Span 3 constructions were made primarily of angular stones, many of which are tuff, set in a mud mortar. There is much less attention devoted to choosing rocks with flat aspects and orienting those faces outwards. Cobbles are also much less commonly used in construction during TS. 3 than was the case in TS. 2. In general, TS. 3 architecture appears to have been more casually fashioned than its TS. 2 counterparts.

Time Span 4

Following Str. 418-5-1st’s abandonment, much of the architecture was covered by the natural accumulation of 0.2-0.37m of hard-compacted, moderately coarse-textured, dark grayish brown loam (S.2). Capping S.2 by 0.06-0.15m is a root-rich dark grayish-brown hard loam (S.1). Embedded in S.1, 2 and the upper 0.14m of S.3 is a moderately dense concentration of stones fallen from final-phase construction (F.1). Feature 1 was traced for as much as 2.8m away from standing architecture.

Chronological Summary