1987 Field Report
(Part
6)
by
Rebecca Jane Dale
NOGAP Archaeologist
Canadian Museum of Civilization
Field No: 85JLP-38
Borden No: MlTk-2
Location: lac à la Truite
As mentioned at the beginning of this report, our first base camp was
established on the point which constitutes the MlTk-2 site. The
opportunity was thus afforded to re-examine, once again, the site locality
for additional evidence of human occupation, and undertake some key
investigations of a previously recorded semi-subterranean feature.
Structure No.2
When this site was discovered in 1985,
both historic and prehistoric remains were recorded (Pilon 1985:28). The
former consisted of a log cabin (used from at least 1966 through to the
present) and its associated scatter of debris. Chert flakes and calcined
bone in a fallen tree root indicated the presence of a prehistoric
component.
During the summer of 1986 we established a
base camp on this site from which we tested other sites in the western
portion of lac à la Truite (Pilon1987). We thus had the opportunity to
re-examine this ridge in greater detail. In this way, we discovered three
semi-subterranean features which seemed associated with distinct clusters
of adze-cut stumps. Two of these features were tested. Unfortunately,
these preliminary studies did not yield conclusive evidence regarding the
methods of construction or the function(s) of the structures. In fact,
more questions were generated than were answered. As a result, it was
decided that during the summer of 1987 we would excavated a large area
within one of these semi-subterranean features in order to clarify our
understanding of them. As it was, we hypothesized that such
semi-subterranean features were likely the remains of dwellings. An
alternate interpretation viewed these depressions as ground caches (D.
Clark personal communication, 1986). We did establish that the feature we
intented to excavate was prehistoric in age. The rings from a live tree
growing on the ridge surrounding the depression were counted and they
yielded an age in excess of 230 years (Pilon 1987:100). Therefore this
feature had to have been built and utilized at an earlier period.
A) Methods
A grid system was established over the depression whose main axes
quartered the feature, with a north-south line on the short axis of the
depression and an east-west line following the long axis. From these base
lines, we laid out four 2 m x 2 m squares with an additional 10 cm baulk
left unexcavated between adjacent units (Units A-D). In this way, we could
obtain continuous profiles along the major axes of the feature. A fifth
2 m x 2 m unit (Unit E) was placed six metres north of the structure. In
digging this unit it was hoped that a culturally undisturbed stratigraphic
sequence would be obtained. Later, two additional 2 m x 2 m units (Units
H and I) were excavated in order to obtain further data on the placement
of the poles which had been recorded in Units A through D. An extra 20 cm
was left between these two new squares (H and I) and Units C and D in
order to prevent the collapse of the profile. Two 1 m x 2 m units (Units
F and G) were placed along the outer periphery of the berm so that the
actual extent of this deposit could be determined.
Excavation was conducted by trowelling according to the natural
stratigraphy of the site. When wooden remains were encountered,
grapefruit knives and paint brushes were used in addititon to the trowels.
We pedestalled all wood and bark remains, and cross-sectioned features and
possible post-moulds
Two major problems impeded excavation and diminished the quality of the
data: permafrost and tree roots. The former slowed excavation while the
ground thawed and the water resulting from the thawing obscured the
deposits below it, while the latter, combined with frost heaving and
cracking, tended to complicate the stratigraphic sequence.
B) Stratigraphy
The vegetation covering this ridge reflects the underlying soil type. For the most part, this terrace is covered by an open spruce-lichen forest. The recent cabin occupation has resulted in the cutting of many trees in the area surrounding the cabin. Low lying areas is carpeted with sphagnum moss and bushes while lichens and spruce trees predominate on the higher and better drained areas.
Level I, the modern vegetation layer (sod) varied in thickness depending upon the type vegetation cover. On high well drained areas lichens predominate while the low lying wet areas and the depression had a thick carpet of sphagnum moss. The sod ranged from 10-30 cm in thickness below sphagnum moss and was considerably thinner (2-5 cm) under the lichens. Level I consisted of two recognizable components. The upper component was the vegetation and associated root mat, while the lower component was a thinner humus containing charcoal and burnt wood. This charcoal and burnt wood component was found uniformly throughout the excavated area and is assumed to be the result of a forest fire(s).
Immediately below this humic material was Level III. This horizon consisted of a reddish coloured coarse sand with pebbles which increased in size with depth. The thickness of Level III was only determined at the edge of the depression in Unit C. It was approximately 25 cm in thickness and was underlain by a basal gravel and sand (Level IV) of undetermined thickness.
The stratigraphy adjacent to the depression differs from that just described in that there were two additional levels present which result from the construction of the semi-subterranean structure; Level II and Level IA. Level II consisted of a light yellow-brown coarse sand with a higher gravel and pebble content (most less than 5 cm in diameter) than Level III. It contained most of the pole remains, as well as bits of charcoal, burnt wood and bark. Level IA was not continuous throughout the excavated area, but was only found under Level II deposits. Level IA consisted of the remains of a humus level.
Level II deposits constituted a berm or ridge surrounding the edges of the depression. They were thickest along the sides of the depression and thinnest at the ends. In cross-section the berm was convex on top, with the base conforming to the natural topography of the terrain. The lateral edges of the berm tended to be steeper along the edge of the depression while the outer margins tapered gradually. The berm attained a maximum thickness of 20-25 cm. Levels III and IV deposits, excavated from the area of the depression, were probably the source of Level II with the cobbles and pebbles being derived from Level IV and the sand coming from Level III.
Very little could be said about the stratigraphic sequence within the depression, due to the problems resulting from the presence of permafrost. The thick layer of sphagnum moss and underlying peat within the depression thawed very slowly and the excavation rapidly filled with water. The constant seepage of water not only slowed down the thaw rate, it also made controlled excavation almost impossible. The depression was dug as deep as time constraints and thawing permitted. The gray gravel and sand of Level IV was encountered and excavated where possible. We able to determine, from the way that the walls of the depression truncated the stratigraphy, that this was not a natural depression.
C) Extant Wood
Pole remains were found in all units immediately adjacent to the depression. Most occurred within the berm deposit (Level II) although some were found on or under this level. The poles had been cut from fairly large trees (with maximum diameters of approximately 10 cm) and judging from the preserved pieces, we can be reasonably certain that their length exceeded the length of the depression. Some of these poles also showed evidence of burning and charring. The lack of poles within the limits of the depression may be due to the preservation conditions and the way the structure collapsed. The poles which spanned the depression would not have been supported after falling, nor would they have been covered with a sandy deposit. Those sections would thus have been more vulnerable to decay and fragmentation, eventually being reduced to small wooden fragments.
The disposition of the poles exhibited patterning. The most consistent arrangement was seen along the northern and western edges of the depression, while less patterning was evident along the southern and eastern edges. On the northern side of the depression the poles were aligned parallel to the long axis of the depression. The directions of a few pieces differed markedly, but for the most part these were smaller fragments. The poles on the west side had the same orientation as those along the north side, however, these were much shorter, truncated at the edge of the depression.
Wood preservation along the south and east side of the depression was quite poor compared to the other two sides. This may help explain the lack of patterning in the poles of these areas. On the south side, the poles displayed only a vague parallel patterning while it was clearer to the east. Much of the wood in Unit A was burned and charred, and there were large patches of charcoal staining found in Level II (the berm).
Two possible post-moulds were found in Level III of the southern halves of Units A and I. Aligned with the two possible post-moulds was an upright piece of wood. Within the depression very little wood was recorded. Those pieces found were either small fragments located in the water and gravel mixture at the base of the depression or else small poles/boughs found sticking out of the depression. The latter were found fairly close to the surface and in a vertical position or lying on the slope of the slumped walls of the depression.
Only one large piece of bark was found in the excavations. It was located along the southern portion of the western wall of Unit B. There were small pieces of birch bark found throughout the area around the depression. In particular several pieces of birch-bark were found between the logs in Unit C.
Finally, what appeared to be spruce boughs were found under the eastern portion of the berm in Unit A. They might represent some type of bedding for a sleeping platform.
D) Artifacts
Levels IA and II contained most of the artifacts. The collection consists of a biface preform, two notched tablets, a core tool and debitage. On the north side of the depression Level II produced one chert nodule and one piece of debitage. A single piece of debitage was found at the interface between Level IA/II, and another was found at the top of Level III.
A greater number of artifacts was found on the south side of the depression. Here, Level II contained the biface preform, one of the notched tablets, the core tool, a retouched split pebble, and a piece of debitage. A retouched flake and three pieces of debitage were found within a gray sand lense, contained in Level IA of Unit B. The top 5 cm of Level III produced a second notched tablet and a single piece of debitage.
E) Summary
Although the excavations described above do not offer any definite solutions to the problems posed earlier, a number of elements are worth repeating as they reflect on the intentions of the builders of the structure.
The first point may appear self-evident, but must be made. The structure is indeed a semi-subterranean feature. Although we could not adequately investigate the interior of the depression, the profiles show quite clearly that the natural stratigraphy had been truncated by digging through these layers to a depth of approximately 50 cm. The site inhabitants did not make use of an existing natural depression, nor was the depression merely an illusion created by the presence of lateral earth ridges (berms). Enough of an area was exposed to allow us to determine that the depression was rectangular and measured approximately 3.5 m x 1.9 m with steeply sloping sides. Branches or sticks may have been placed in the bottom of the depression.
The soil which had once filled the depression was not scattered about, but appears to have been an important element in the construction of this feature. Indeed, both soil and spruce poles seem to have been combined in a carefully planned fashion. It resulted, that following use and eventual decay of the structure, the long poles were aligned parallel to the length of the depression with thick deposits of sand and gravel following the same orientation. This very clear patterning is proof that this is not a haphazard occurrence.
The berm was thickest along the sides of the depression. Although also present either end, berm deposites were much thinner in those areas. It is important to note that some of the berm material was found under the poles, but most of it was found on top of them.
Elsewhere, it has been argued that the absence of significant pole remains within the confines of the depression (as well as the presence of scattered wood fragments) can be attributed to the lack of support for such spanning elements as well as the resulting exposure to agents of decay, which would include fire. Judging from the arrangement of the extant wood remains in the northern portion of the excavations, poles greatly exceeding the length of the depression were used. Estimated basal diameters in excess of 10 cm indicate that substantial efforts were expended in order to secure an adequate supply of poles. Moreover, it is assumed that the cluster of adze-cut stumps in the vicinity of this structure are the very trees which were cut to provide construction materials to the builders.
The artifacts found in the excavated area were not particularly helpful in determining the function of this feature. No diagnostic artifacts were recovered. The artifacts occurred in Levels II, IA and the top few centimetres of Level III. Those found in Levels IA and III represent a previous occupation of the area, Level II artifacts are likely derived from the earlier use of the locality and would have been redeposited during the original excavation of the depression by the later occupants. Alternately, this small number of ubiquitous items may have been left by the inhabitants of the semi-subterranean structure.
F) Discussion
The size, complexity, and elaborateness involved in the construction of this semi-subterranean feature argues that it was more than just a ground cache. In fact, the only common element shared between the two types of features is that they are both, from an archaeological persepctive, depressions in the ground.
The semi-subterranean structure appears to have been constructed in the following manner. A large rectangular depression was dug into the ground with the dirt being saved for use as roofing material. Substantial trees from the general vicinity were felled with stone adzes. These poles were used to construct a roof which covered an area greatly exceeding the length and width of the depression, thereby significantly increasing the living area within the structure
The design of the roof support structure can only be guessed at, but the disposition of the poles and the berm deposits strongly suggest that roof was of a gabled type. It would have minimally consisted of two A-frames spanning the long axis of the structure with the long poles placed lengthwise between these supports. The latter may have been tied to secure them into place, while the possible post-moulds and the upright piece of wood found in the souther nunits may represent bracing stakes. The reserved sand and gravel was then placed on top of the poles whose interstices may have been chinked with sod. The ends of the structure may have consisted of short poles leaned against the roof or of skins. The entrance could have been from either end.
Following abandonment, some of the roofing sand eventually worked its way between the roofing poles and was deposited on the old soil surface. However, most of this dirt seems to have slid down to the base of the roof, in a fairly even way on either side, thus creating the lateral berms. With time, the roof collapsed, but the poles maintained their relative arrangement. The lateral ridges of sand and gravel were slowly eroded by the elements and came to cove rmost of the poles. Some of these, however, remained exposed and were eventually destroyed beyond recognition by natural decay processes and fire.
Additional excavations were conducted in proximity to Structure No.2 in
1991.
