3.6.2 The Grubenhäuser

Fig. 3.12 A small group of Grubenhäuser in the craft zone, in the north-western part of the settlement Introduction

Fig. 3.13 Excavated Grubenhäus

Over 125 Grubenhäuser have been examined. Of these, 125 were classed as definite with an additional five features considered as possible Grubenhäuser. More than 700 contexts were derived from the Grubenhäuser, excluding those that relate to their associated post-holes, and although this represents less than 5% of the record, these features contained nearly 20% of the finds assemblage. These features are ubiquitous within Early Anglo-Saxon contexts and are, in contrast to the post-hole structures, extensively paralleled on sites in continental Europe. Their structural form, comprising a large sub-rectangular pit with associated post-holes, and the fact that they have provided the source for the majority of Early Anglo-Saxon artefactual material from settlement sites, have ensured that they have been widely recognised. Recognition and comprehension have, however, not gone hand in hand; early excavators such as E. T. Leeds believed that these 'holes in the ground' provided shelter and housing for a migrant population, an interpretation which is now quite unacceptable. The presence of large quantities of artefacts within the fills of the Grubenhäuser prompted a number of excavators to provide functional interpretations based on the derived material; however, the current evidence shows that this was again an unacceptable conceptual leap.

The suggestion made by Stanley West during the excavation at West Stow, Suffolk, that some of these structures incorporated supported floors, is important with reference to their interpretation, and at West Heslerton there is no evidence to suggest that the base of the pit formed a floor in any of the excavated examples (West 1985). Indeed, there is no direct evidence to support the suggestion that the material contained within the pits was actually associated with the function of the structure as a whole, although there is some indication from the plant macrofossil evidence of contrasts from one part of the site to another that may provide clues about the function of at least some of these structures.

In a number of cases a major secondary use for the pit can be identified prior to the in-filling of the pit. In one case, a shallow hearth covering more than a third of the base of the pit may indicate conversion of a cavity-floor structure to a smokehouse; in another, a pit which provided shelter from all sides except the east had an oven constructed within it; in a third example, cut into chalk, a later Grubenhaüs on a slightly different alignment replaced an earlier structure which had evidently been completely filled prior to the construction of the later structure.

Fig. 3.14 One of several examples where an early Grubenhaüs has been replaced by a later post-hole structure Structural form

The basic set of forms for Grubenhäuser are well known, with two-post, four-post and six-post settings and their derivatives covering almost all the known examples. All the examples at West Heslerton can be classified as two-post, although in a number of cases repairs are indicated by the evidence for additional posts both within the pit itself and adjacent to the primary axial or gable posts at each end. The location of the Grubenhäuser shows a consistent although not exclusive distribution, with most of the structures being constructed in sand or gravel environments rather than on the solid chalk bedrock that dominated the areas located to the east of the stream channel.

Although there is evidence for digging of post-holes and packing of the gable-posts in at least some of the structures, the posts often appear to have been driven into the ground as piles, a feature which has a considerable bearing on any reconstruction of the superstructure. The lack of detailed evidence relating to the form of the superstructure is problematic and is likely to remain unresolved until a good example that has been fully burnt or waterlogged is discovered.

Fig. 3.15 Large Grubenhaüs with evidence of re-cutting

Evidence for large cut timbers has been identified in the larger examples, indicating at least that they were carefully constructed. In one example the deposits around the structure and a number of possible post settings beyond the area defined by the pit were interpreted at the time of excavation as possibly relating to the construction of a turf dwarf-wall, but the evidence was far from clear and re-examination of all the structures within their local context is required before promoting this interpretation as anything more than a possibility. At the southern end of the site where hill-wash deposits and the presence of the medieval field headland had ensured a better state of preservation, pebble surfaces adjacent to a two-phase Grubenhaüs may indicate that access to the structure was through the long side of the structure and not at the gable-end. In at least three cases, a Grubenhaüs had been replaced by the construction of a post-hole structure of broadly similar proportions. The largest Grubenhäuser have overall dimensions which closely match some of the smaller post-hole structures and it is quite possible in these cases that the superstructure may not have been dissimilar, the major gable posts providing an anchor for a tie beam structure rather than major supports. In the case of those cut into sand a considerable eaves gap, as would occur had the roofs been thatched, would have been necessary to prevent the pit from heavy erosion around the sides that, at best, had only minimal stability. There was no evidence of wicker or plank linings to the pits in any of the excavated examples, although in the sandy areas it would have been easy to interpret some of the many worm-holes within the pits as stake-holes. If we accept that these structures were cavity floor buildings, and the evidence points only towards this conclusion, then the lack of any structural impact on the ground surface around the pit implies that some sort of horizontal beam arrangement existed at ground level, spreading the load of the structure as a whole and reducing the need for additional supports set into the ground. A simple arrangement would be the construction of a timber-framed box tied across the short axis at the base of the walls and at the sill height. Such a structure would be strong and leave minimal ground impact.

There was no evidence of internal structural features such as benches, steps and the like in the bases of the Grubenhäuser, which have been put forward in reference to similar sites in the past. Likewise, there was no evidence to indicate that the Grubenhäuser had had hearths constructed within them. One example contained a large body of burnt clay/marl with a finished surface; this deposit is paralleled by a deposit interpreted as a hearth at West Stow. In this case the source of the material was identified some five metres away in the form of a malt-kiln, the large lumps of burnt material apparently being derived from the destruction of the kiln top.

There is a tremendous variation in the size of these features ranging from not much more than 1.5m x 1m to 7.5m x 4.75m. The variation in scale is also reflected in the depth, which varies from just a few centimetres to over 1.6m. The variation in depth cannot simply be a function of varying degrees of plough damage or subsoil conditions, although the deepest examples were found within 35m of the spring and may have needed a deeper cavity in what may have been damper conditions. This variation in overall volume has a considerable bearing on the assemblage analysis where there is clearly a need to quantify assemblages by feature volume. Raw materials

The question of the form of the superstructures has a considerable bearing on the raw materials used to construct these buildings. The low frequency of daub from the site in general has been noted above and it seems unlikely that these small structures were furnished with wattle-and-daub walls. That the major upright timbers were of cut timber can be demonstrated for a handful of the structures examined. As with the post-hole structures, a variety of materials for roof construction were available locally, and it is hoped through detailed examination of the plant macrofossil evidence and charcoal to review the evidence for the construction of the superstructures in the light of the experimental evidence generated from the reconstructions that have been standing for a number of years at the West Stow Country Park. Function of the Grubenhäuser

Fig. 3.16 Pre-excavation Grubenhaüs showing distribution of animal bones

The interpretation of the function of the Grubenhäuser has in the past hinged largely on a subgroup of the material recovered from the excavated pits; since it is now clear that the deposits which fill the pits post-date the demise of the structures, this aspect can be re-examined. One objective in the detailed environmental sampling of the Grubenhäuser fills was to attempt to use this data in order to interpret the local context of the Grubenhäuser and to study the formation processes related to the filling of the pits. It was argued that the pits from the decaying Grubenhäuser provided a catchment zone for plant macrofossil data which might help in interpreting localised site function, if not in providing some evidence of the function of these structures. One aspect identified in Wendy Carruthers' assessment of the plant macrofossil evidence is the relative frequency of wheat between areas to the west and east of the stream channel that bisected the settlement. If the summary indication that wheat has a higher concentration in the Grubenhäuser located to the east of the stream channel is confirmed, this may give added weight to the suggestion that at least a percentage of these structures were utilised as grain storage buildings. The physical environmental requirements for grain storage are adequately dealt with in a cavity floor structure of the type envisaged here.

imageFig. 3.17 Unfired clay loomweights

The interpretation of the Grubenhäuser as weaving sheds, put forward by Leeds and others in the past (e.g. Leeds 1936, appears to derive from a selective interpretation of the evidence, both the discovery of loom-weights and the survival of the considerably later celebrated series of letters between Charlemagne and Offa pertaining to the trade in cloth and Niedermendig lava querns. Certainly loom-weights, both fired and unfired, were found in many of the Grubenhäuser at West Heslerton; however, they were generally found in association with large quantities of animal bone, often articulated fragments of skeletons which must have rotted in situ, coprolites etc., which indicate that these were essentially waste deposits. The discovery at Sutton Courtney of a series of loom-weights threaded onto a carbonized stick or rod need not point to the function of the structure as a weaving shed; the temporary storage of loom-weights, most of which were unfired, on a stick or rod would seem quite sensible and the same data could easily be interpreted as a discarded group of weights, rather than something directly related to the structure. At West Heslerton, where loom-weights were of local clay available within 100m of the settlement, it would have been easier to create new weights than to repair damaged dried weights, which would explain the frequent discard of these objects. Clearly, spinning and weaving were a part of the economic life of West Heslerton; this, however, needs to be quantified if we are not to give this activity too great an importance in the life of the settlement. The regional textile tradition is documented in the archaeological record from the Iron Age onwards and need not be seen as much more than a local craft/industry primarily concerned with local needs. There can be no doubt that the Grubenhäuser were multi-functional structures and their use as general storage buildings sometimes related to spinning and weaving is not contested. The distribution of discarded loom-weights shows a marked concentration in the north-west portion of the settlement; however the correlation between this distribution and the high density of Grubenhäuser, which formed ready-made rubbish pits once the structures had gone out of use, may reflect discard policy rather than localised site function.

The suggestion that the Grubenhäuser provided housing for a low status population has been put forward in the past. This seems unlikely given the environmental conditions prevailing in the craft/industrial zone for instance. Large quantities of animal bone, including whole carcasses, were recovered from both the Grubenhäuser and the surfaces around them, and high levels of organic disturbance in the fills of the Grubenhäuser combined with the animal bone evidence indicates that once the structures had gone out of use they were filled with festering rubbish. Higham has argued that these features were simply root cellars and not structures in any real sense of the word and, although this explains the evidently minimal structural components, this interpretation seems most unlikely (Higham 1991).

If we argue that the Grubenhäuser were general purpose structures associated with the full range of crafts and agricultural processing, then the high concentration of Grubenhäuser in the north-west part of the settlement suggests that this area was the focus for a variety of different activities including spinning and weaving, metalworking and animal processing, as well as butchery and no doubt leather, bone and horn working (see also 3.8 Environmental Data, 4.1 Plant Macrofossils, 4.2 Charcoal Assessment, 4.3 Faunal Remains Assessment, 4.4 Assessment of Soils). Structural decay

There was little clear evidence to document the decay of the Grubenhäuser. In some cases, where the post-pipes remained well defined, it appears that the base of the posts decayed in situ; for most of the structures the evidence was less categorical and, given the shallow nature of many of the post-holes, it is possible that many may simply have been pulled out without leaving any readily identifiable trace.

The pits, which form the most distinctive feature of the Grubenhäuser, ultimately served to dispose of rubbish; only a small number of other pits relating to the Early Anglo-Saxon occupation of the site were identified, and these appear to relate to quarrying, particularly to extract a distinctive deposit of iron-rich red chalk and clay. In the excavation at West Stow, West identified a 'standard tripartite filling sequence' in the Grubenhäuser. A similar sequence of fills was identified at West Heslerton, particularly where the structures had been cut into sand and were filled with primarily sandy deposits. It is possible that the appearance of the layers within these Grubenhäuser had undergone post-depositional change, with organic material leaching out of the upper fills to be concentrated towards the base of the features. The sandy soil component itself was hardly different from the top to the base of the features, the distinguishing characteristic being primarily related to soil colour. Detailed comparison between the Grubenhäuser cut into chalk and sand will need to be undertaken to clarify this aspect of the site formation process.

The Grubenhäuser in their final form, as rubbish pits, represent the most important context group on the site on account of their single-phase fillings and the wealth of cultural and environmental evidence recovered from them.

The fills of each Grubenhaüs appear to represent a relatively short-lived filling event; had they filled gradually then we would anticipate quite a different fill sequence with more evidence of the collapse of the sides of the pits and influx of aeolian sands and other materials from adjacent surfaces. Two Grubenhäuser situated along the north-eastern limit of the occupation area were distinctive in that they contained few finds and a relatively large amount of blown sand, indicating that they had been left open and filled naturally rather than as a consequence of deliberate rubbish disposal. Even here there was little erosion of the sides of the pits, indicating that the rapid deposition of aeolian sands that can be witnessed today was probably also a characteristic of the Early Anglo-Saxon landscape. In one case, in Area 11CC, a construction sequence for two adjacent Grubenhäuser can be postulated from the partial filling of one pit with re-deposited natural tipped in along the edge closest to the adjacent structure. This was readily observed in the field since rarely did these features contain any obvious re-deposited material, thus raising questions concerning the considerable volumes of natural that would have been extracted in the initial cutting of the pits (see also 4.1 Plant Macrofossils, 4.2 Charcoal Assessment, 4.3 Faunal Remains Assessment, 4.4 Assessment of Soils, 4.6 Coprolite Assessment) The Grubenhäuser: a primary data set

The detailed analysis of the cultural and environmental material derived from the Grubenhäuser will be pivotal to the identification of the overall development sequence of the settlement during the Early Anglo-Saxon phase. Differences in the faunal, plant macrofossil and artefact data from different parts of the site have been identified in the assessments; it appears that these differences reflect both variations in status as well as different localised functionality. The integrated analysis of the whole assemblages from the Grubenhäuser needs to be viewed both within the context of West Heslerton and with reference to other similar sites of the period where the assemblages are lacking key components such as faunal material in the case of Mucking, or plant macrofossil data from both West Stow and Mucking. The relative distribution of bird-bones, for instance, appears to relate to social status, although their relative infrequency in the northern part of the settlement coincides to some degree with the presence of sandy subsoils. The abrasive and well-ventilated soils in the north-western part of the settlement have contributed towards differential preservation of the faunal assemblage which may have reduced the survival level of the slight bird bones; they are not, however, altogether absent from these areas. West Heslerton provides an unparalleled opportunity for an integrated approach to the analysis of the cultural and environmental assemblages from a site of this class. Although there was clearly considerable bioturbation, in part a product of the decay of the organic materials within the Grubenhäuser fills, each feature represents an individual 'time-capsule'. The comparison between the material derived from the relatively undisturbed Grubenhäuser fills and the surface midden deposits offers important potential for the study of fragmentation (see also 4.1 Plant Macrofossils, 4.2 Charcoal Assessment).


© Internet Archaeology URL:
Last updated: Tue Dec 15 1998