SMR 176 / NS 949 795
Extraction of material by a mechanical excavator from a clay pit at the foot of Polmonthill to the south of the road from Old Polmont to Avondale, immediately opposite to Jinkabout Bridge, in January-February 1940 revealed a huge deposit of oyster shells. At the time of the excavation the area was not wooded. The shell heap was approximately 170yd long from west to east, and 25yd wide. It was 3-4ft thick and lay under a 2-3ft layer of hill-wash. The natural clay and boulder base of the midden lay at 32ft OD, rising in the south to 47ft. The shells were mostly oysters, but mussels, winkles, cockles and a few buckies occurred.
Thin layers of burnt material showed that this was a midden rather than a natural sea-borne deposit. In these layers were burnt stones; and flat stones had been laid to form hearths. One burnt deposit lay in the shelter of a large boulder. The burnt layers were more common on the uphill side of the midden and in once instance there were four superimposed layers. Samples of the charcoal were identified as oak. Beyond the edge of the shells, some of it uphill, but more particularly beyond the western and eastern ends of the heap, was a spread of black matter, apparently burnt, up to over 1ft thick, containing no shells but numerous heat-fractured pebbles, some as large as two fists.
A large pit was found dug through the shells, measuring around 7ft deep and 9ft wide, with vertical sides – the north side had been removed by the mechanical digger before the pit was recognised and it is possible that it lay open on that side. The natural clay at its base had been reddened by heat, and above this was a 6in layer of ash. This may have been a lime kiln utilising the shells as the source of the calcium carbonate.
The midden lay on the old beach line and is one of several on the line of the old beach on either side of the River Avon, including Inveravon, Kinneil, Northfoot and Mumrills. It is possible that part of the shell midden remains, but if so it will be very little. The oyster shells observed by Sloane in 1985 may simply have been those discarded in 1940 during the search for the clay at the base.
Bibliography
| Stevenson, R.B.K. | 1946 | ‘A Shell Heap at Polmonthill, Falkirk,’ Proc Soc Antiq Scot 80, 135-139. |
| CECA | 1985 | Discovery and Excavation in Scotland, p.6 “Fieldwork has suggested that there may be surviving in situ deposits from this site, thought to have been totally destroyed in 1940. Further apparently in situ madden deposits were noted at NS 949 796 and NS 9485 7965.” |
Falkirk Local History Society 