Palaeoecology Research Services Technical report: The implications of macro- invertebrates, mainly insects, from medieval and early post-medieval deposits at Morton Lane, Beverley, East Riding of Yorkshire (site code: MLA01) PRS 2003/58 Palaeoecology Research Services PRS 2003/58 Technical report: The implications of macro-invertebrates, mainly insects, from medieval and early post-medieval deposits at Morton Lane, Beverley, East Riding of Yorkshire (site code: MLA01) by Harry Kenward and John Carrott Summary An archaeological excavation was carried out by Archaeological Services, WYAS, at Morton Lane, Beverley, East Riding of Yorkshire, between the 17th of September and the 16th of November 2001. This report considers the invertebrate remains (mainly insects) recovered from deposits of medieval and early post-medieval date. Of twelve samples processed, six gave interpretatively valuable assemblages of invertebrate remains. These have contributed to the interpretation of the individual features from which they came (providing evidence of both the immediate environment and human activity), but also have wider relevance to the site and beyond. Four of the species present are regarded as perhaps of climatic significance, being north of their generally known range in the 21st century. Although perhaps under-recorded in the North, these species are so very common in archaeological deposits that it may be argued that, even if present in the area now, their abundances have changed greatly, climate change being one reasonable explanation. The record of a single head of the beetle Prostomis mandibularis, from Context 1239 is most unusual. Unknown in modern Britain, this species is an ‘urwaldiere’, associated in mainland Europe with very decayed wood in ancient forests. This record requires careful evaluation since it would move the species forward into the second millennium AD, rather than being a first millennium BC extinction as formerly supposed. KEYWORDS: MORTON LANE; BEVERLEY; EAST RIDING OF YORKSHIRE; TECHNICAL REPORT; MEDIEVAL; EARLY POST-MEDIEVAL; MID 12TH TO LATE 15TH CENTURY; INVERTEBRATE REMAINS; INSECTS; CLIMATE CHANGE; PROSTOMIS MANDIBULARIS Contact address for authors: Prepared for: Palaeoecology Research Services Archaeological Services, WYAS Unit 8 P. O. Box 30 Dabble Duck Industrial Estate Nepshaw Lane South Shildon Morley County Durham DL4 2RA Leeds LS27 0UG 16 July 2003 Palaeoecology Research Services 2003/58 Technical report: Morton Lane, Beverley Technical report: The implications of macro-invertebrates, mainly insects, from medieval and early post-medieval deposits at Morton Lane, Beverley, East Riding of Yorkshire (site code: MLA01) Introduction remains, and all of these have been recorded in detail. An archaeological excavation was carried out by Archaeological Services, WYAS, at Morton Lane (to the north and east of its Methods junction with New Walkergate), Beverley, East Riding of Yorkshire (NGR TA 033 398), The sediment samples (‘GBA’/‘BS’ sensu between the 17th of September and the 16th of Dobney et al. 1992) were inspected in the November 2001. laboratory and descriptions of their lithologies were recorded using a standard pro forma. Two trenches were excavated revealing a Subsamples were processed, following the complex series of deposits and features mostly procedures of Kenward et al. (1980; 1986) for of medieval date. Extensive stratified deposits the recovery of invertebrate macrofossils. were examined throughout the site and multiple phases of use and occupation were Flots, and sometimes washovers, from twelve noted. subsamples were reviewed and detailed analysis made where appropriate: six Dates obtained from pottery recovered from a contained more than a trace of invertebrate number of small pits and a shallow gully gave remains. These assemblages are discussed a mid 12th century date for the earliest below. Sediment descriptions and results for occupation. the 'barren' subsamples are given in Table 1. Of particular interest, from the point of view Remains were identified in the flot (for of the invertebrate remains, were the later pit familiar species) or placed on damp filter fills. Some of the pits had been used for the paper for more careful inspection where disposal of large amounts of refuse (in the late necessary. The remains of adult beetles and 12th to mid 13th century – Phase III) and many bugs were ‘detail’ recorded in the terminology of their fills gave strong hints of deposition of Kenward (1992), and a record of under waterlogged conditions. One of two preservational condition made using the scales later pits (late 15th century – Phase IV) gave presented by Kenward and Large (1998). remains which suggested that it had been used Fossils were identified by comparison with for hemp retting. There appears to have been modern reference material and using the no activity at the site throughout the 14th standard works. Adult beetles and bugs, other century. than aphids and scale insects, were recorded fully quantitatively and a minimum number of An assessment of two samples from the site individuals estimated on the basis of the was carried out by Hall et al. (2002), fragments present. Other invertebrate following which a decision was made to carry macrofossils were usually recorded semi- into a main phase of analysis in which an quantitatively using the scale described by initial review of a series of samples would be Kenward et al. (1986) and Kenward (1992), followed by targetted detailed study. In the again using estimates for extremely abundant event only six samples (of 12 submitted) were taxa. Data pertaining to invertebrate remains productive of more than traces of invertebrate were recorded directly or transferred from a paper record to computer databases (using 2 Palaeoecology Research Services 2003/58 Technical report: Morton Lane, Beverley Paradox software) for analysis and long-term typical of buildings of various kinds has been storage. termed ‘house fauna’ (Kenward and Hall 1995). The interpretative methods employed were essentially the same as those used in work on The quantification of an ‘outdoor’ component a variety of sites by Hall, Kenward and co- in what are sometimes clearly natural or semi- workers (see Kenward 1978, with natural assemblages may not appear entirely modifications outlined by, for example, logical, but in fact is useful when working Kenward 1982; 1988; Hall and Kenward with any deposits associated, even if rather 1990; and Kenward and Hall 1995). indirectly, with human occupation. Interpretation rests primarily on a number of ‘main statistics’ of whole assemblages of adult The abundance of these ‘ecological’ groups is beetles and bugs, and on the recognition of discussed against the background of values for ecologically-related groups of species. The many other assemblages from a large number main statistics used include: (a) a measure of of sites. Thus, % N OB = 30 is a high value, species-richness (or diversity), α of Fisher et but % N RT = 30 is low; while % N W and % al. (1943), for the whole assemblage and for N RF are both high at 10. components of it; and (b) proportions of ‘outdoor’ species (OB, calculated from taxa The index of diversity offers a guide to the coded oa and ob), aquatics (W, w), waterside presence or absence of remains of insects species (D, d), phytophages (plant-feeders) which bred in or on the developing deposit (P, p), species associated with dead wood (autochthones), low values indicating breeding (L, l), moorland/heathland taxa (M, m), and communities, high ones faunas of mixed decomposers (species associated with origins. Note that ‘significantly’ low values decomposing matter of some kind). differ for the various components of Decomposers are subdivided into (a) species assemblages; the more inherently rich a primarily associated with somewhat dry component is, the higher the value of the habitats (RD, rd), (b) those found mostly in index of diversity for a living community will rather, to very, foul habitats (RF, rf), and (c) a be. Thus, ‘outdoor’ communities associated residuum not easily assignable to one of these with natural vegetation tend to give a high (rt). The category ‘RT’ includes all three of value of α, while very specialised these groups of decomposers (rt + rd + rf). In communities, such as those of decaying matter each case, the lower-case codes (e.g. ‘rd’) are deposited by humans, or stored grain, have those applied to species and the upper-case low or very low ones. codes (‘RD’) are for the ecological group. A further ecological component quantified for Results the present site was the synanthropes, i.e. those species favoured by human activity The results are presented in date order by (Kenward 1997). Taxa have been assigned phase and, in the case of multiple fills of the codes for degree of synanthropy as follows: same feature, lowest first. Archaeological ‘sf’—facultative synanthrope, common in information, provided by the excavator, is natural as well as artificial habitats; ‘st’— given in square brackets. A brief summary of typically synanthropic, but able to live in the processing method and an estimate of the nature; ‘ss’—strong synanthrope, absent from remaining volume of unprocessed sediment or very rare in natural habitats in the relevant follows (in round brackets) after the sample geographical area. These codes give rise to numbers. ecological groups SF, ST, and SS, which are summed to give SA (all synanthropes). A group of synanthropes regarded as particularly 3 Palaeoecology Research Services 2003/58 Technical report: Morton Lane, Beverley Sample numbers for the two samples from varying) moisture content. A few aquatics were present, perhaps of background origin (having arrived in flight), Context 5006 were created by PRS and were or perhaps from imported water. The latter explanation derived from their positions within the presumably applies to the Daphnia ephippia (water flea deposit: Sample 4050 – 40 to 50 cm from the resting eggs), which must have arrived passively. Two top of the context, and Sample 5060 – 50 to 60 other components were present in small numbers but cm from the top of the context.