Reports from the Environmental Archaeology Unit, York 97/30, 15 Pp
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Reports from the Environmental Archaeology Unit, York 97/30, 15 pp. Technical report. Insect remains from the Seamer Carr landfill site: ecological reconstruction of a Mesolithic shore. by Harry Kenward and Frances Large Summary Insect remains from six samples from the Mesolithic littoral deposits at Seamer Carr, near Scarborough, N. Yorkshire, have been reviewed and one of the assemblages recorded in detail. Context 147 from Trench 83 provided a large assemblage of insect remains, although most were rather poorly preserved. The predominant component was of species associated with open water and emergent vegetation, indicating a fen environment. The island seems to have supported some scrub. There was evidence of areas of short grass, most probably resulting from human clearance then trampling. Adoxus obscurus, a leaf beetle only recently found alive in Britain, was recorded. Keywords: SEAMER CARR NEAR SCARBOROUGH; MESOLITHIC; SHORELINE; ANALYSIS; INSECTS; CLEARANCE; ADOXUS (BROMIUS) OBSCURUS Authors’ address: Prepared for: Environmental Archaeology Unit Northern Archaeological Associates University of York 15 Redwell Court Heslington Harmire Road York Barnard Castle YO1 5DD Co. Durham DL12 8BN Telephone: (01904) 433843/51 Fax: (01904) 433850 30 November 1997 Reports from the EAU, York 97/30 Insect remains from Seamer Carr Technical report. Insect remains from the Seamer Carr landfill site: ecological reconstruction of a Mesolithic shore by Harry Kenward and Frances Large Introduction The laboratory evaluation During October 1996 excavations were The samples were examined in the carried out by Northern Archaeological laboratory, where they were described Associates at Seamer Carr, near using a pro forma and six were chosen for Scarborough, N. Yorkshire, as part of an processing to extract insect and other evaluation of the archaeological potential macroinvertebrate remains, Subsamples of of an area proposed for development as a 1 kg were used in each case, and methods landfill site. Members of the Environmental followed Kenward et al. (1980), as Archaeology Unit were engaged in an modified by Kenward et al. (1986). advisory capacity, and on 17.10.96 visited the site and collected samples from a series Extracted fossils were examined in the of trenches exposing organic deposits ‘flot’ recovered by paraffin flotation, the abutting and overlying a low ‘island’ of material being stored in industrial gravel believed to represent what was methylated spirits. A record was made of formerly an area of dry land formerly the preservational condition of the remains, surrounded by fen. The primary interest of of the range and abundance of fossils the deposits lay in their association with representing various ecological groups, and Mesolithic flint scatters, paralleling of the principal taxa (Carrott et al. 1996). material recorded elsewhere in the Vale of One of the assemblages (Sample 868 from Pickering, notably at the classic site at Starr Context 147, Trench 83) was selected as Carr, but there was clearly also substantial having particular value in reconstructing biological potential. the past ecology of the site providing a larger subsample was processed, and The samples, ‘GBAs’ sensu Dobney et al. subsequently funding was made available (1992), were collected from Trenches 83, for its investigation. 80, 82 and 48, representing a series from south to north from the former swamp or Insect remains from the earlier excavations lake upslope onto the gravel island. Single at Seamer were described by Osborne samples were collected from thin, (1980). apparently wasted, peats in Trenches 48 (Sample 419) and 82 (815), three from the Analysis rather thicker sequence in Trench 80 (1094- 6), and five from a much better developed The bulk of the remaining material for sequence of muds and peats in Trench 83 Sample 868 (5.1 kg) was subjected to (866-9). In Trenches 80 and 83, the paraffin floatation and the resultant flot samples were numbered down the sorted for insect remains. The fossils were sequence. placed on damp filter paper for identification, and beetles and bugs listed 2 Reports from the EAU, York 97/30 Insect remains from Seamer Carr together with the minimum number of might provide sufficient remains for individuals able to provide the recorded ecological reconstruction. parts. The numbers of other invertebrate groups were estimated semi-quantitatively Sample 868, Context 147 (see Kenward et al. 1986; Kenward 1992). Sediment description: Moist dark grey Results and discussion (often browner internally) soft, fibrous amorphous organic sediment with traces of (1) The evaluation stones in the 6-20 mm range. The sediment appeared ‘jumbled’ (?disturbance at the The results are considered by trench from lake edge) and contained abundant downslope to upslope, and within trenches herbaceous detritus and some sandy from below to above. The sediment patches. 1 kg processed. descriptions are those made in the laboratory prior to processing. The flot was of rather modest size and was rich in insect remains. Preservation ranged Trench 83 from rather poor to quite good, but in all cases the remains were in sufficiently good An irregularity in the floor of this trench condition for identification. Aquatic, appeared perhaps to represent a wave-cut waterside/swamp and terrestrial beetles and shoreline. The lowest sample (869) was bugs were abundant and rather diverse. The taken from beneath muds suspected on the concentration of water beetles and bugs basis of field observation to have formed in was sufficiently high in terms of both the lake shallows, the muds themselves individuals and species for a very precise being represented by Sample 868. Sample reconstruction of conditions to be made 867 included a thin horizon overlying the using a larger subsample, and similarly the putative lake muds together with the lowest range of waterside insects promised a clear peats, while the remaining samples were view of the local aquatic marginal taken from higher levels within the peat. vegetation. The fauna of a larger subsample is considered in detail below. Sample 869, Context 183 Sample 867, Contexts 101/148 Sediment description: Moist mid to dark grey (browner internally) fibrous sandy, Sediment description: This sample silty, amorphous organic sediment. represented the base of the peat and the Appreciable quantities of stones in the 2-60 somewhat greenish layer beneath it. Moist, mm range. 1 kg processed. dark grey-brown, fibrous but brittle, greasy (working crumbly then plastic) amorphous A large volume of plant debris was organic sediment with herbaceous detritus recovered in the flot. There were only a few locally throughout. 1 kg processed. beetle remains, forming no clear ecological community, and a small number of other A rather large flot resulted from paraffin invertebrates. The rarity of remains did not extraction. It contained a small number of appear to have resulted from in-ground insect remains of variable preservation decay, as none of the remains showed (although all were in an identifiable state). extreme chemical degradation. It was There were some aquatic, waterside and estimated that a subsample of about 20 kg probable terrestrial taxa. A very large subsample (say 20 kg) would be needed to 3 Reports from the EAU, York 97/30 Insect remains from Seamer Carr recover an interpretable assemblage, Sample 1094, Context 106 although even then it is not certain that sufficient terrestrial species would be Sediment description: Amorphous organic recovered for ecological reconstruction sediment with some wood; although moist beyond the point of deposition to be it appeared to have dried out in the past. accurate. Not processed. Sample 866, Context 101 Trench 82 Sediment description: Dark brown Sample 815, Context 141 compressed and layered amorphous organic sediment with abundant woody and Sediment description: Moist; variable in herbaceous detritus. Not processed. colour from dark slightly grey yellowish brown to dark brown, crumbly (working Trench 80 soft and plastic), silty amorphous organic sediment with traces of sand locally; in Sample 1096, Context 130 places pure amorphous organic matter. Some wood was noted. 1 kg processed. Sediment description: Mid to dark greyish brown (locally strong brown and pale The flot was large and contained abundant grey), soft and plastic to crumbly (working course fragments of plant root and ?stem. plastic) amorphous organic sediment, with There were traces of invertebrate remains. some humic silty sand and grades between It was considered doubtful whether even a these extremes. Trace of flint. 1 kg 20 kg subsample would produce an processed. interpretable assemblage of insects, although some information would be The flot was large, consisting of what obtained. appeared to be fragments of fine plant roots, but only a single insect fragment was Trench 48 noted. Low input seems unlikely to be the cause of this extreme rarity invertebrates. Sample 419, Context 101 There were no partly decayed remains, but it is possible that the deposit had undergone Sediment description: The sample was just extreme humification at some stage, moist and the sediment appeared to have destroying the content of fossils, and then undergone decay locally. It was a dark (or at the same time) had been invaded by strong brown in colour, brittle, apparently plant roots. indurated, amorphous organic sediment. There was some bark and wood. 1 kg Sample 1095, Context 129 processed. Sediment description: Amorphous organic The flot was