Uncovering one of the largest Mesolithic Sites in the UK
Field-walking was carried out after ploughing and after the soil had been weathered. Thesoildoesneedtobe‘weathered’.Heavyrainexposestheflintsbywashingawayfiner-grained material. The flints also show up better if they are wet. Walkinganewlyploughedfieldmayshowlittleornolithicmaterial,andcouldgiveaverywrong assessment. We know this from experience.Notes made by Roger Daly on John Grieve’s collections mention that he fieldwalked after heavy rain.Use of hand-held GPS DuringfieldwalkingwithOFARSatKinclune,JamesKenworthyintroducedus totheuseofhand-heldGPSforrecordingthegridreferenceofeachfind.Thismethodwasinitiatedbyhimin2003atGoryHill,andweemployedthe same method at Crathes. Asthescatterswerequiteintensiveoverlargepartsoftheareawefoundit moreefficientforeachpersontohavetheirownGPS,althoughthiswasnot alwayspossible.ThedifferentGPSswereaccurateto2-3mandcorrelated well. Gridreferencesweretakenalongtheedgesofallthefieldswalked.Ialso tookGRsalongthehigherandlowerareasofNM3inanattempttogivean approximation of possible river braiding. Wethinkusinghand-heldGPSisaveryeffectiveandsimplefieldwalkingmethodforshowingthespreadand intensityofflintscattersinplough-soilandthereforetoberecommendedandidealforamateurs.Vicki Cummings(2010)usedhand-heldGPSinasimilarmannertousandalsoadvocatesthismethod.Thegrid referencescouldthenbeusedtocompile10mx10msquaresandcalculatethetotalnumberoflithicsin each square.
RecordingIusedMicrosoftExcelforthecataloguingandrecordingofattributes,thelithicsscatterplotsandconcentration charts.ScatterplotsThescatterplots,usingtheExcel‘Scatterchart’,werecompileddirectlyfromthegridreferences(yaxis: Northings;xaxis;Eastings).Thisisveryquickandusefulmethodforindicatingthespreadoverthearea covered.However,thisdoesnotgiveanaccuraterepresentationofnumbers,asfindswiththesamegrid reference will show as only one 'find-point' on the chart. Itcanalsobeusedformorespecifictaskssuchasshowingthelocationsofcores(forexample)overthearea, or even finds from 1 person's 'walk' on a particular day.Concentration chartsTheconcentrationchartswereplottedasthenumberofflintsper10mx10msquare,aswefeltthisgaveusa good picture of the area taking into account the accuracy of the GPS and the fact that the flints were not in situ. Thetotalspersquarewerecalculatedbysummingthenumbersoflithicsfoundateachrelevantgrid reference. Comparison of scatterplots and concentration chartsAsmentionedabove,thescatterplotsdonotgiveanaccuraterepresentationofnumbers,whereasthe concentrationchartsrepresenttheactualnumbersfoundper10mx10msquare.Themoreintensethescatter, the more the discrepancy increases (see the figure below).
Figure The total number of flints and the number of grid references per each 10mx10m square along a transect from NM 1, 2008: Northings 96 (check) and Eastings 75860 - 75209.
Table: Brief summary of fields and areas walked
At 2m apart
Preliminary: W and S edges
W and S edges, extending further into the field
Some line walking in rest of field
N half of field, including terrace
S half of field
Part of intensive area in N half of field
Brief survey along the terrace; unweathered soil
Most of the terrace and adjacent area
N bank, ridge and part of S half of the field
Terrace and adjacent areas including N bank
N and S parts of the field
Brief walk through East end of terrace
All the field except N end and extreme S edge
N end of field
S W corner, W edge, and narrow strip along S edge; also part near NW corner
Some very brief line walking over rest of field
Very brief survey round edges and across diagonal
Areas walkedFieldwalkinginthe1980shadgivenussomeideaofscatterlocations;someline-walkingtoandfromthestrips tobeinvestigatedsystematicallyaddedtothisinformation.Walkingat2mapartwasmainlyfocussedonthe terraceandadjacentareas.Otherareaswerecoveredlessintensively.Thetablebelowgivesanindicationof theareaswalkedduringthefiveyearsurvey.Detailsoftheareasinvestigatedareincludedwiththerelevant concentration charts, and a diary of of the fieldwalking with numbers of flints
OFARSmembersfield-walkinginNM1 alongthemiddleterrace;thebankofthe upperterraceistheothersideofthewall (top right) in NM 1A
Fieldwalking methodsSystematicfieldwalkingisrecommendedtoenablecomparisonstobemadewithothercollections.Various method can be used, such as line walking, measured areas, total collection. Weoptedfortotalcollection,followingJames’procedureusinghand-heldGPS,andwalking2mapartusing furrowsasguidelineswhereverpossible.Eachflintwasindividuallybaggedand,tosavetime,labelledwith justtheGRco-ordinatesandfinder'sinitialsandkeptbythefinder.Whereflintswerewithin1mofeach othertheywereputintothesamebag.Afterwards,attheendofeachsession,finderswereeachallocateda larger bag, labelled with the date, site, field number and his/her initials to contain their finds. Later,Irinsedthefinds(manyweremuddy),brieflylookedatthem,andreplacedthemintheirbags, transferringany‘extras’totheirownindividualbags.Alltherelevantinformation(i.e.site,fieldno.,GR,date and finder’s initials) was added to each bag where necessary.
Photo: P Fawcett
Select the buttons below to view the fieldwalking progression through NM 1
NM 1, with NM 1A bottom right. Photo: P Fawcett
NB Typing error: the top left grid reference should of course be 748.