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BGS Technical Report WA/97/03 15 December 1997 These red mottled clays are interpreted as relicts of the Ipswichian temperate Hykeham Soil (see above under Etwall Sand and Gravel). Up to 3.6 m of sand and gravel were formerly worked from the extensive Redland’s Hargate House Pit [c. 260 3051, situated to the east. This pit is now Milled and fully restored to agriculture. McCullagh (1968, figure 1) undertook a pebble count on the gravel from this pit. The count is interpreted here to be: Bunter quartzite and quartz, 70%; sandstone (probably comprising mostly Upper Carboniferous and Bunter Pebble suite rocks), 19%; Lower Carboniferous limestone, 2%; flint, 3%; Lower Carboniferous chert, 5%; igneous rocks, 1%. . During the course of the survey, sections were seen in cuttings [2660 3083 to 2695 30701 along the Derby Southern Bypass near Tynefield Court, to the south of Etwall. The deposit was also seen in deep excavations for a bridge over Egginton Road [c. 2690 30721. These sections showed, below c. 0.3 m of sandy gravelly soil, up to 2 m of buff-coloured, passing down to deep orange-brown, coarse-grained, ill-sorted, cobbly, sandy, silty gravel over red mudstone. The basal c. 1 m of the gravel was reddish orange-brown and clayey. The gravel contained some indistinct sand lenses. In the uppermost c. 1 m the gravel was totally decalcified and strongly cryogenically involuted with vertically arranged stones. Locally the gravel was very clayey in the top 0.5 m. The clay was mostly mottled grey and buff and contained vertically arranged stones, but at one point [2684 30731 also contained red blotches, interpreted to be rubification associated with Hykeham Soil development (see above under Etwall Sand and Gravel). The gravel clasts were mostly of Bunter quartzite and quartz and flints, the latter invariably frostshattered. At one point [2696 30691, east of the Egginton Road, c. 1 m of gravel was apparently undisturbed and exhibited imbrication indicating a palaeocurrent towards 096 O. On Egginton Common [c. 274 3001 much of the deposit has been worked out (see Mineral Resources section). Numerous boreholes in the worked out area indicated greatly varying thicknesses of gravel from 0 to 4.3 m. Much of the gravel was clayey and interspersed with red clay. In the Egginton Common area the clasts comprise mainly Bunter pebbles (c. 85%) and frost-shattered flints (c. 5%). The remainder of the clasts were composed of chert, and sandstones fiom the Mercia Mustone Group and Upper Carboniferous. Two flint handaxes were found by the writer on the reject pile at the Redland Aggregates Etwall Pit [273 2971 during 1994 (Wessex Archaeology, in press). The deposits exposed in this Etwall pit were the subject of field work over several years by Mr P F Jones of Derby University; the bulk of the results are not published. He has found a number of flint hand-axes at the pit (Jones, oral communication 1990). Notes on a geological excursion to this pit [275 3001 (Jones et al., 1979) were as follows: ‘The gravels were poorly stratified and highly disturbed in a form suggestive of severe periglacial disruption. They made a strong contrast with the low-lying terrace and floodplain sediments. It was mentioned that lumps of ‘boulder clay’ had been recorded in the Hilton gravels during earlier excavations (Posnansky, 1960). Members of the excursion examined a discontinuous surficial layer of pebbly clay and there was much discussion (particularly amongst the leaders) whether this constituted a till or a solifluction earth. The problem was unresolved. Nevertheless it was noted that the apparently simple planar surface of the terraceis misleading since it obscures a complex internal structure.’ A further excursion report on Etwall Gravel Pit [grid reference erroneously given as 275 3091 24
BGS Technical Report WA/97/03 15 December 1997 (Jones, 1981), which was supposedly located on the ‘Upper Hilton Terrace’, states ‘Approximately 3 m of coarse ochreous gravels rest on Triassic bedrock. The gravels are poorly stratified and highly disturbed in a form suggestive of severe periglacial disruption. Lumps of included ‘boulder clay’ were reported by Posnansky (1960) from a nearby site (2 km SE) but have not been recorded here.’ It continues: ‘Borehole and geophysical investigations in connection with earlier workings on Eggington Common (1.5 km S) showed that the gravels in that area occupy a series of sinuous channels. These are over 5 m deep and form a dendritic pattern with an apparent drainage direction of E - W (ie opposite the flow the modern river). The borehole logs also record the occasional presence of pebbly red clays at different horizons within the gravel sequence. While the origin of these deposits is not clear, discontinuous surficial layers of pebbly clay exposed in shallow pits on Egginton Common have been interpreted as solifluction earths. Such records do not support the view that the Hilton Terrace had a conventional fluvial origin.’ It is suggested here that the dendritic ‘channel’ pattern possibly results from severe post-depositional periglacial disruption. 5.2.4 Holme Pierrepont Sand and Gravel The thalwegs and long profiles of this terrace deposit are illustrated in Figure 4. This deposit was graded to a lower base level than Flandrian Trent deposits and as a consequence both underlies the latter and forms a dissected terrace, c. 1-2 m high, bordering the Hemington Terrace. The deposit was previously referred to as (deposits of) the Floodplain Terrace (Swinnerton, 1937) and the Floodplain Sand and Gravel (Brandon & Sumbler, 1988) but was renamed the Holme Pierrepont Sand and Gravel by Charsley et al. (1990). The Holme Pierrepont Sand and Gravel comprises generally pink, ill-sorted, matrix-supported, sandy, trough cross-bedded gravels and is interpreted as a braid plain distal sandur deposit from the late Devensian ice front situated above Burton upon Trent in the Trent valley and near Uttoxeter in the Dove valley. Details: Its outcrop just barely enters the south-western corner of the sheet area at Hilton Depot and no sections were encountered. 5.2.5 River Terrace Deposits, undifferentiated A small area of River Terrace Deposits has been mapped adjacent to Etwall Brook, just to the north-east of Dalbury [2589 34571. The deposit comprises sandy, gravelly clay and forms a terrace slightly elevated above the clay alluvium of Etwall Brook. 5.3 Alluvium All the streams of the area are associated with narrow tracts of floodplain alluvial deposits, typically between 100 m and 250 m in width. The named streams of the area are Etwall Brook and its tributaries, the Trusley and Rwlbourne brooks. These alluvial deposits typically comprise c. 1 m of greyish brown, grey, reddish brown or buff, clayey, stoneless silt overlying c. 1 m 25
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