Continental trace fossils and museum exhibits - Geological Curators ...

Figure 24. The 1 m 2 stringed grid being used to measure and draw the track surfaces. The large feature on the far sideof the block is a sauropod track.Figure 25. A mini-blackboard with block number and feature number. The scale bar is 0.1 m.I was fortunate enough to be on holiday in the areasoon after their discovery and was able to visit thesite. Armed with brushes, the features were sweptclear of debris revealing a considerable number oftracks (Figure 3).The University of Portsmouth visited the site early onand carried out some recording. The National Trust(whose land was leased by Kevin Keates) involvedthe University of Bristol and, as a result, Dr JoWright, then based at Bristol, was commissioned todocument the site. A short report was published(Wright 1998). Once recorded, and after an open daywhen the public could view the discovery, the sitewas reburied in situ in order to preserve it for thefuture.Belle Vue Quarry – 1997 to date: The discovery ofidentical prints to those seen at Keates’ Quarry at thesame horizon heralded the start of what continues tobe a fascinating opportunity to watch a quarry develop,exposing a succession of bedding planes through the‘Middle Purbeck Beds’ with tracks preserved asmoulds or casts, and other features includingmicrovertebrate horizons. Through the kindness ofthe owners, Mr and Mrs W. T. Haysom, access hasbeen freely given and research at this site is ongoing.Track-bearing pavements have been recovered andare being held by the Haysoms.The Isle of Portland dinosaur tracks – 2002 todate: During 2002, tipped blocks of Purbeck limestonefrom the ‘Thick Slatt’ were observed to have dinosaurtracks on one of their lower surface. The author, thenemployed by the NHM, was invited by RichardEdmonds, on behalf of Dorset County Council, toassist with the recording and decision making processwhich would lead to the recovery of these specimens.The recording was carried out in 2003/04 and prioritylists made for the recovery of the blocks.The recording process started with a check of thenumbering of the blocks identified as having trackspreserved on their lower surface. Some blocks hadbeen numbered with a spray can, as used in the stoneindustry, as they were lifted from the heaps of tippedstone where they had first been spotted. Those thathad been omitted at this stage were added to thesequence and, as an insurance, the numbers werecarved with hammer and chisel into the sides of theblocks. The recording of the track surfaces was carriedout using a 1 m 2 stringed grid which was laid on thesurface with data being transferred to squared paperat a scale of 1:10 (Figure 24). Polythene plans weremade of each block; these are available as templatesin planning displays in the future. Photography wascarried out when the sun was low in the sky to providea raking light, showing the features to best effect.With only a short period of time with optimumlighting, and over 100 features to record, this requiredconsiderable speed, and a method for identifyingeach feature and the block it was on. To achieve this,a set of tiny black-boards (0.045 x 0.09 m) weremade. These had the block number and featurereference denoted by a letter, as previously allocatedon the plans of the blocks, written in blackboardchalk. A general oblique view was taken of eachblock before individual features were recorded (Figure25). A 0.1 m scale bar with cm gradations wasincluded in each picture. The blackboards could bewiped clean with a damp cloth and recycled veryquickly.The tracks are preserved as ‘casts’ on the base of athick bed of limestone. Unfortunately, only a smallpercentage of the original blocks of limestone fromthis bed were preserved at the time of extraction,sometime before their discovery! Trying to makesense of the remaining pieces can be likened tohaving a 100 piece jigsaw, throwing away 95 pieces,-239-