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Excursion to Westcombe Park, Greenwich, and Loampit Hill, Lewisham
112
EXCURSION TO WESTCOMBE PARK, GREENWICH, AND LOAMPIT HILL, LEWISHAM. APRIL 7TH,
Director: T. V. (Report by
188&.
HOLMES,
Esq., F.G.S.
THE DIRECTOR.)
As the sections at Westcombe Park are described in 'Proc. Geol. Asscc.,' Vol. viii., No.1 (Jan., 1883), and those of Loampit Hill are among the best-known in the neighbourhood of London, a very brief report will suffice here. A large party assembled at Westeombe Park railway-station, the day being remarkably fine. The two chalk-pits a few yards eastward of the station were first visited. The dip of the Chalk, as indicated by the layers of flint, is, in this neighbourhood, slight in amount and southerly in direction, and the same remark applies to the dip of the overlying Lower Tertiary beds. Only a little Thanet Sand, however, is seen overlying the chalk in either pit. After leaving the chalk-pits Westcombe Park was entered from its eastern boundary, and its sections viewed in the order in which they are described in our 'Proceedings: Since their examination by the Director in November, 1882, they had been cut further back and modified in various ways, the result being to show the great variability as regards minute detail of the Woolwich and Blackheath Beds. A word of caution may perhaps be useful on the way in which the Blackheath Pebble-Beds mask the beds beneath them along the brow of the Lower Tertiary escarpment. The pebbles roll down the hillside in vast numbers, and give the impression that it is entirely made up of pebble-beds, where no road or railway-cutting exists to show the true state of things. Thus in a guide-book to Greenwich and its neighbourhood, published last year, is a remark about "One Tree Hill" in Greenwich Park, to the effect that " owing to a peculiarity of its geological formation it is composed principally of loose pebbles." Now One Tree Hill is simply a part of the westerly extension of the Westcombe Park escarpment, and is similarly composed of Thanet Sand, and Wool. wich and Blackheath Beds. But the slopes on th6 northern face of One Tree Hill, having been much neglected and allowed to become
EXCURSION TO
113
WESTCOMRE PARK, ETC.
entirely bare of grass, appear to consist of Blackheath Pebble Beds from top to bottom, in consequence of the immense quantities of pebbles that have rolled downhill. Leaving Westcombe Park by Foyle Road, the party walked through a corner of Greenwich Park, and, after leaving it by the Blackheath gate, crossed the Heath and descended the hill towards Lewisham. On reaching the immediate neighbourhood of the Loampit Hill sections, it became evident to all who had visited the locality before that great alterations were in progress there. Much building is going on close to the most easterly pit, that in which the shell-beds of the Woolwich series and strata immediately below them are displayed. This pit is now enclosed, and used as a store yard. But as it is, fortunately, nearly semi-circular in shape, the party were enabled to get a good view of the strata from the top of the pit. The oyster bed, 2ft. thick, separating the two Cyrena beds, was pointed out and contrasted with the mere trace of an oyster bed atWestcombe Park. Below the shell-beds and that containing "race" and concretions, a thick pebble-bed was seen, but, above the shell-beds, the thick pebble-beds of W estcombe Park were represented at Loampit Hill by a pebble band of 2in. to 3in. at the base of the London Clay. We were fortunate at Loampit Hill on this occasion in seeing a new and very clear section of the strata between the Woolwich shell-beds and the London Clay. They consist, as described by Mr. Whitaker (' Geology of the London Basin,' p. 127), of laminated clay with partings of sand and sand with partings of clay, having a total thickness of about 25ft. After glancing at the pits showing the London Clay, and at that in which the Chalk and Thanet Sand appear, the party dispersed in the direction of the St. John's or Lewisham railwaystations.
8
EXCURSION TO WESTCOMBE PARK, GREENWICH, AND LOAMPIT HILL, LEWISHAM. APRIL 7TH,
Director: T. V. (Report by
188&.
HOLMES,
Esq., F.G.S.
THE DIRECTOR.)
As the sections at Westcombe Park are described in 'Proc. Geol. Asscc.,' Vol. viii., No.1 (Jan., 1883), and those of Loampit Hill are among the best-known in the neighbourhood of London, a very brief report will suffice here. A large party assembled at Westeombe Park railway-station, the day being remarkably fine. The two chalk-pits a few yards eastward of the station were first visited. The dip of the Chalk, as indicated by the layers of flint, is, in this neighbourhood, slight in amount and southerly in direction, and the same remark applies to the dip of the overlying Lower Tertiary beds. Only a little Thanet Sand, however, is seen overlying the chalk in either pit. After leaving the chalk-pits Westcombe Park was entered from its eastern boundary, and its sections viewed in the order in which they are described in our 'Proceedings: Since their examination by the Director in November, 1882, they had been cut further back and modified in various ways, the result being to show the great variability as regards minute detail of the Woolwich and Blackheath Beds. A word of caution may perhaps be useful on the way in which the Blackheath Pebble-Beds mask the beds beneath them along the brow of the Lower Tertiary escarpment. The pebbles roll down the hillside in vast numbers, and give the impression that it is entirely made up of pebble-beds, where no road or railway-cutting exists to show the true state of things. Thus in a guide-book to Greenwich and its neighbourhood, published last year, is a remark about "One Tree Hill" in Greenwich Park, to the effect that " owing to a peculiarity of its geological formation it is composed principally of loose pebbles." Now One Tree Hill is simply a part of the westerly extension of the Westcombe Park escarpment, and is similarly composed of Thanet Sand, and Wool. wich and Blackheath Beds. But the slopes on th6 northern face of One Tree Hill, having been much neglected and allowed to become
EXCURSION TO
113
WESTCOMRE PARK, ETC.
entirely bare of grass, appear to consist of Blackheath Pebble Beds from top to bottom, in consequence of the immense quantities of pebbles that have rolled downhill. Leaving Westcombe Park by Foyle Road, the party walked through a corner of Greenwich Park, and, after leaving it by the Blackheath gate, crossed the Heath and descended the hill towards Lewisham. On reaching the immediate neighbourhood of the Loampit Hill sections, it became evident to all who had visited the locality before that great alterations were in progress there. Much building is going on close to the most easterly pit, that in which the shell-beds of the Woolwich series and strata immediately below them are displayed. This pit is now enclosed, and used as a store yard. But as it is, fortunately, nearly semi-circular in shape, the party were enabled to get a good view of the strata from the top of the pit. The oyster bed, 2ft. thick, separating the two Cyrena beds, was pointed out and contrasted with the mere trace of an oyster bed atWestcombe Park. Below the shell-beds and that containing "race" and concretions, a thick pebble-bed was seen, but, above the shell-beds, the thick pebble-beds of W estcombe Park were represented at Loampit Hill by a pebble band of 2in. to 3in. at the base of the London Clay. We were fortunate at Loampit Hill on this occasion in seeing a new and very clear section of the strata between the Woolwich shell-beds and the London Clay. They consist, as described by Mr. Whitaker (' Geology of the London Basin,' p. 127), of laminated clay with partings of sand and sand with partings of clay, having a total thickness of about 25ft. After glancing at the pits showing the London Clay, and at that in which the Chalk and Thanet Sand appear, the party dispersed in the direction of the St. John's or Lewisham railwaystations.
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