Excavation

Date 5 April 2010 - 15 October 2010

Event ID 632929

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/632929

NK 007 257 and NK 008 261 Two short pilot seasons of fieldwork were carried out on the shell middens and

surrounding soils of the Sands of Forvie on 5–10 April and 11–15 October 2010. The middens in the Ythan estuary have been known of since at least the 19th century and three large middens were identified in 2005, during survey work led by Graeme Warren (Warren 2005, 65–6). The April fieldwork concentrated on the most threatened of these, Midden C, a large eroding face of mussel midden, located near the present shoreline limit.

Excavations at C showed that the midden sequence consisted of 2.9m of deposits, extending for over 35m in

length. This sequence was established through two main columns excavated to the lowest deposits. The most visible and obvious part of the midden was a c0.6m band of stratified shell deposits in the upper portion of the eroding section. This upper midden lay on top of a significant sand dune (up to c1.3m deep), which had formed above a series of earlier more discrete shell deposits. Various pits were found dug into the sand dune, one of which, an intact fire pit, consisted of a layer of fire-cracked stones on top of a charcoal deposit. This has been interpreted as a steaming pit used to open the mussels for consumption, as found in many ethnographic contexts. There were few finds apart from a net sinker in the lowest level and one or two lithic pieces, including one in the fire pit. Six radiocarbon dates were obtained from the lowest levels to the upper parts of

the upper midden deposits. The basal charcoal-rich layer dated to 325–555 cal AD with all the layers above this

forming rapidly in the period of 715–985 cal AD. Samples of shells, sediment micromorphology samples and pollen samples were taken from Midden C.

Further assessment work was carried out on Middens A and B in October 2010. Midden A is a low roughly circular mound, c20m in diameter, located on the main raised beach (MPGT). Within three test pits located on the western face of the midden, two major shell midden layers were found slumping down the raised beach. The midden layers, like those at Midden C, were located on top of a major sand blow event, suggesting that this midden is also likely to be of later date, probably in the 1st millennium AD. The only finds were intrusive pieces of Victorian glass. The midden composition was identical to that of Midden C and pits were also found cut into the lower sand dune layers.

Midden B is an irregularly shaped mound, roughly horseshoe in plan, with a depression at its centre. It is c35m

long NW–SE and c10–15m wide NE–SW, with the SW portion of the mound eroding down the MPGT raised shoreline. This midden, like the other two middens was mainly made up of mussel shell with a small percentage of periwinkle and the occasional cockle. Five test pits were excavated, three on the E part of the horseshoe and two near the shoreline edge on the W part of the midden. The midden was much shallower

than A or C, reaching only 0.3m. A maximum of three shell bearing layers were recorded in each test pit. The shell midden layers generally slumped away from the central depression of the horseshoe, which may have been a boggy hollow with a high water table or spring source in the past. In the NE test pit fragments of antler were found at the base of the midden. Fire pits were found dug into the underlying sand layers. One test pit towards the SW limits of the site found midden layers of an unusual character. Here, although dominated by

mussel, there was a much higher percentage of cockle and periwinkle shells and the upper layers also contained animal and fish bone. An iron rivet or nail was also found in this part of the midden, suggesting that this zone may date to the 1st millennium AD or later. While no direct dating evidence is yet available for Middens A and B their similar character and in the case of A construction, on a major sand blow event,

suggests a later date for these middens and they may be found to be contemporary with Midden C. The shells, animal and fish bone from Midden B are currently undergoing analysis.

A series of five soil test pits was excavated in an area c200m NE of Midden A (NK 008 261), to investigate the soils and land use of the surrounding area before, during and after the formation of the middens. This area contains the remains of rig and furrow and a field boundary, in the form of a low linear earthwork on three sides of an irregularly-shaped quadrilateral field. Three test pits were excavated outside of the field, a few metres E of its SE corner: one on top of a rig (Test Pit 1), one at the bottom of a furrow (Test Pit 2), and one on the S edge of a sand dune (Test Pit 3). The field boundary was sectioned on its S side, just a few metres from its SE corner, and a test pit was excavated to investigate the soils buried below it (Test Pit 4). Finally, a test pit was placed on a low rig within the field that was surrounded by the field boundary (Test Pit 5).

The soil sequences in the test pits shared very similar characteristics, with slight differences in their upper

horizons resulting from land use activities in their particular location. The lowest horizon in all the soil test pits was a C horizon consisting of a reddish brown clay loam – a glacial till derived from old red sandstone. Above this was a very dark brown clay loam that may be a weathered B horizon of a brown forest soil. Above this dark brown clay loam was a thick, homogenous dark brown sandy loam that appears to be a manured plough soil, which developed during a period of increased aeolian sand deposition. This agricultural activity predated a major episode of aeolian sand deposition and formation of sand dunes in the area (including the one on top of Test Pit 3), which on the basis of the radiocarbon dates may have occurred sometime in the 1st millennium AD. This windblown sand deposit was subsequently buried in the medieval or post-medieval period by the field boundary, which was constructed of sandy turf and large stones (Test Pit 4). Within the field enclosed by the boundary wall, the windblown sand deposit was completely reworked into an overlying plough soil and there was a very sharp, horizontal contact boundary between this Ap horizon and the underlying, pre-sand dune, prehistoric plough soil. Outside of the field boundary, the windblown sand deposit was truncated by the furrow

observed in Test Pit 2, and was redeposited on top of the adjacent rig (Test Pit 1). Bulk samples for organic and

chemical analyses were taken from each soil horizon in the test pits, soil micromorphology samples were taken from Test Pits 3 and 5, and charcoal samples were taken from the buried Ap horizon. Bulk soil analyses are currently being conducted and funds are being sought for further analyses. The department is also working on proposals to develop work here into a larger multi-period landscape project.

Warren, G. 2005 Recent fieldwork at the Sands of Forvie, Aberdeenshire. Unpublished report.

Archive: University of Aberdeen (current)

Funder: University of Aberdeen and Historic Scotland

G Noble, K Milek and E Philip – University of Aberdeen