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Excursion to Gomshall, Netley Heath, and Clandon
182
EXCURSION TO GOMSHALL, NETLEY HEATH, AND C L A.J.~DO N. SATURDAY, J UNE
Di rector:
25, 1887.
H. H UTCHINS F RENCH, F.G.S.
(R eport by 'fHE
D I RECT OR.)
On alighting at Goms ha ll Station , t he attention of Members was directed to the exposure of fine brigh t- yellow sa nds (Folkestone B eds, L ower Gr een sand) , which are her e worked for use in building, making bricks, &c. F ollowing the r oad to Sher e, keeping the Tillingb ourne on the left-hand and the Cha lk escarp men t on the ri ght, till the r oad opposite the post- offi ce is r eac he d, the party ascend ed the escarpment by Colekitchen L an e. A small expo slLre of F olk estone Beds was seen on t he left; about 100 yards fur th er on a pi t in Ga ult Cl ay (not visit ed) was passed on the ri ght, an d beyond this se vera l small pi ts by the road sid e in Lower Cha lk . J ust beyond wh ere the 400 feet contour line is marked on t he map , a pit on the left -hand is in Melb ourne R ock . T h is wa s carefully exa mined, b ut yi elded no foss ils. It was sta ted , on t he author ity of .Mr. J. F . Ben nett, that exposu res of t h is di vision bed between t he Lower and Middle Cha lk show t hat it is continuous between t his point an d R eigat e. Colek itc he n F ar m is sit uat ed in a bea utif ul Coombe, a nd just befor e descend ing it good vie ws are to be had over t he Gault va lley a nd Lower Gre ensand hill as far as Hindh ead to t he west and over Lei th H ill, to the ea st. P assin g on th rough t he beau tifull y wooded district of t he King's ' Voods, t he s um mit of t he Chalk was r eac hed. H ero t he Ridgeway R oad, a wid e open grass g lade stretc hi ng for mil es east an d west , was crossed, and woods again ent er ed. As the descen t of the northern dip-slope of the Cha lk began , the pa th ra n throug h a pl antation of finely-gro\Yn beech es, down to H oneysu ckl e Bottom, which is skir ted on t he west by a plant ati on of fir t rees, known as Mou nta in Wood. At the northern end of t his wood a halt was made, and us the party rested und er t he shade of t he trees, the Director expla ined a change wh ich th e oflicers of the Survey had found necessary in th e mapping of the
EXCURSION TO GOMSHALL, NETLEY HEATH, AND CLANDON.
183
The alteration related to the extent geology of the district. of ground covered by the large tertiary outlier on N etley Heath. As marked, it extended too far east and south. On re-examination it had been found to cover about one-third only of the space at present shown on the map, and to consist of three detached outliers; the largest in Hook \V ood, with a smaller in Barnet "Vood to tl.o south-west, and a third small patch at Pobley Farm to the north-east. A considerable stretch of "Sands of Doubtful Age" would be marked resting on the Chalk and occupying the area of the rest of the outlier, as at l)resent mapped, extending beyond it south and eastwards nearly as far as Green Dene Farm. The main feature of this visit was to see exposures of these sands, of gravel and associated beds in Hook IV oorl , and the well ut Clundon. Patches of these" Sands" occur along the North Downs from Folkestone to this, their present most westerly known extension. '1'0 what formation they belong has long been debated without any generally accepted solution lHlving been arri vod at. In Professor Prestwich's paper" On the Sands and Iron Sandstones of the North Downs," in 'Q.J.G.S.,' Vol. xiv (1858), pp. 321335, they are claimed as the equivalents of the lowermost (Coralline Crag) beds of the Pliocene of East Anglia. Mr. Whitaker, writing in 1871 on "The Geology of the London Basin" (' Geol. Surv. Menl.,' Vol. iv , Part 1, pp. 336-342), is inclined to place them low down in the Eocenes as overlapping masses of the Woolwich and Oldhaven series. So the question rested until last year, when Mr. Clement Reid published in u: N atui-e " (l2th Aug., 1886) tlte result of his investigation of the beds at Lenham, which thoroughly corroborates Professor Prestwich's view. Speaking of the fossil evidence, Mr. Reid sa,ys: "Thel'e is not a, single Eocene species among them. With two or three exceptions they are all known Pliocene forms, some are new to England, though occurring in France and Italy." The Crag age of the Lenham Beds may now be regarded as established. Professor Prestwich is of opinion that the other patches of Sands of the North Downs, though they differ in character from the Lenham Beds, are all of the same age. As none of them have yielded fossils, the conclusion must be received with some reserve, although other considerations tend to confirm t his view, The position of these
184
EX CURSION TO GOMBHAI ,I" NF.TLEY HF:ATH , AND CI, ANDO l,-
beds, on the summit of t he Chalk Downs, 600 feet above sealevel, indicates t hat t he great va lley of the ·Weald has been excavate d since Pliocene ti mes, t he S ands ha ving , in all pr obability, been derived from t he denudation of a Lower Gre ensand island which ex iste d wh ere the Wealden valley now is. -The following sections were t hen examined : I .-Band.p it B. W. of F ir P lantation ( near R.M., 591-2 on 6in. Ordnance M ap) . 1. Brick-earth , r eplaced in parts by mot tl ed clay, flint gravel, and san d. pocketin g irregularly into t he und erlying sanda, shallow bands of sub-angular flints and p ebbles. frequent at th e ju nction... From Oft. Oin, t o 4ft. Oin. 2. Yellow-brown ferruginous sands, apparent ly false-bedded... Seen to 6ft. 6in.
This section showed that the sands were of earlier date than the "drift," and lat er than the Lower Tertiaries, which occur within half a mil e of the pit and differ from t hem in colour and lithological cha raeter . In r eply to Rev. A . Irving, wh o claimed t hem as B agsh ots, it was pointed out t hat th ey occur re d at a lower level th an th e Tertiaries of t he dist ri ct , an d as the London Clay was believed to be present in B arn et W ood (wit hi n t hre e-quarters of a mil e west, at an elevat ion of 674 feet ) , t he suggestion would imply considerable cont emp orane ous erosion. In t he abse nce of fossil evidence, it was impossibl e to det ermin e t heir age within t he ab ove limit s j but r egar ding them as the equivalents of t he Lenham Beds they would be classed as Crag. I Io-Pit N .W. end of Fir Plantation, about 540ft. above 1. Cappi ng of soil ... 2. Bro wn cla yey sand enclosing t wo irregul ar mas ses (4f t. x lift . and Skft . x IHt.) of red-blu e mould clay (apparently derived fr om Woolwich and Reading beds) 3. Ochreous sands ...
Ordnance Datum. a fe w inches.
1 t o 6 feet . ju st seen.
'I'he excavation is not sufficient ly deep to allow of t he connection between Beds 2 and ;j being made out with certainty, but Bed 2 appears to cnt and pocket into Bed 3. Bed 2, on the other side of t he pit, contains rounded flint pebbles and" pebbles" of cha lk, some of the latter being Bin, long, though gen erally smaller.
EXOURSION TO OOMSHAJ,f,. NETLEY HEATH, ANn CLANDON.
185
III.-Gravel Pit on summit of hill in Hook Wood, on road from Woodeote Lodge to Fuller's Farm, about 678ft. above Ordnance Datum. 1. Capping of mottled clay, sand, and flint
2. 3.
4.
S. 6.
gravel, irregularly mixed up, and in more or less wavy lines Irregularly waved band of gravel cutting into under. lying bed Compact clay (?brickearth) with small broken angular pieces of white flint and a few" nodules" of chalk 6in.long ... Gravel composed of small (white) well-rounded .flint pebbles, with a large admixture (disseminated through the mass) of medium-sized and very large water-worn flints Hard brown clayey sand Gravel alternating with light-coloured sand," much obscured by talus. The limits of each division consequently undeterminable
6ft. From lin. to Ift,
3ft. 6in.
3ft.6in. 1ft.Oin.
About 6ft.
Skirting Hook Wood, a small exposure of Woolwich and Reading Beds was seen in a pond at Fuller's Farm. Continuing round Barnet Wood, where mottled clay is to be seen, Merrow Downs were crossed, whence fine views across the Thames Valley are obtained when the atmosphere is clear, and Clandon was reached in time to view the spoil-heaps of the well which has been sunk for the W oking Waterworks Company. By the courtesy of the contractors, Messrs. Quill, we are enabled to give the following sections from particulars supplied by their foreman, Mr. Langton, who kept a most careful diary of the strata passed through as the work proceeded. IV.-Section of Clandon Welt (Woking Waterioorlcs Company).
1. Soil 2. Flints and yellow loamy clay 3. BLUE (LONDON) CLAY... Thirteen bands of Septaria were passed through the nodules measured more than Sft. across.) Black loamy sand and a little water A few pebbles and a little water Traces of sand Veins of sand with water Veins of sand with water Veins of sand Reddish clay Few shells... Basement bed, well-rounded black pebbles
2ft. Oin. Sft. Oin, 224ft. Oin, (some of at 30ft. \
I""'
at 121ft. at 133ft. ~. at 138ft. I .£ ~~ ~ Q) " at 143ft. I o::l III at 203ft. s o::l at 215ft. ~ at 219ft. ... Oft. nin .
I
J
.. The sands are well seen iu rabbit-holes on the south side of hill.
186
EXCUHSION TO GOMSHALL, NETLEY HEATH, AND CLANDON.
4. WooT,wIeR AND R~ADING BRDS Compact bed of shells and clay ... Compact bed of sbells and limestone Mottled clay, blue and brown Do. red and bluish Do. brown and blue Do. buff and brown Do. light blue and red . Very dark clay, spotted brown . Mottled clay, red and buff Do. pinky-red and slate Very hard Iight-blne clay Pink and light-blue clay ... Mottled clay, becoming sandy towards base
*
Hard loamy Greensand . Hard grey yellow sand . Sandy green loam mottled brown Hard Greensand, dry and loamy, with scattered shells, much broken ... Thin bed of small well-rounded dark flint pebbles Greenish loamy clayey sand Clean grey sand full of water Green-coated flints
1 ft.l 11ft. ) 3 ft., 1 ft. 2 ft. 4 ft. 4 ft., 9 ft 5 ft: 1 ft. 2 ft.
r
83ft.
Oin,
314ft.
6in.
66ft.
4~ft.
30~ft.J 2!ft'l L,ft. I
To Chalk
ff
t·l
41 ft .
~
14~ft.
Ut.)
2ft. 2ft. I
¥t.J
REFERENCES. Geological Survey Map, Sheet 8. Ordnance Survey :Map, new series, Sheet 285. WBITAKF:R.-" Geology of the London Babin" (' Melli. Geo1. Snrv.,' Vol. iv), " At tbe deptb of 2(j9~ft. the diary was discontinued, but was resumed agaiu at 300ft. When the well was first dug, water rose and overflowed to 10ft. above the surface of the ground.
EXCURSION TO GOMSHALL, NETLEY HEATH, AND C L A.J.~DO N. SATURDAY, J UNE
Di rector:
25, 1887.
H. H UTCHINS F RENCH, F.G.S.
(R eport by 'fHE
D I RECT OR.)
On alighting at Goms ha ll Station , t he attention of Members was directed to the exposure of fine brigh t- yellow sa nds (Folkestone B eds, L ower Gr een sand) , which are her e worked for use in building, making bricks, &c. F ollowing the r oad to Sher e, keeping the Tillingb ourne on the left-hand and the Cha lk escarp men t on the ri ght, till the r oad opposite the post- offi ce is r eac he d, the party ascend ed the escarpment by Colekitchen L an e. A small expo slLre of F olk estone Beds was seen on t he left; about 100 yards fur th er on a pi t in Ga ult Cl ay (not visit ed) was passed on the ri ght, an d beyond this se vera l small pi ts by the road sid e in Lower Cha lk . J ust beyond wh ere the 400 feet contour line is marked on t he map , a pit on the left -hand is in Melb ourne R ock . T h is wa s carefully exa mined, b ut yi elded no foss ils. It was sta ted , on t he author ity of .Mr. J. F . Ben nett, that exposu res of t h is di vision bed between t he Lower and Middle Cha lk show t hat it is continuous between t his point an d R eigat e. Colek itc he n F ar m is sit uat ed in a bea utif ul Coombe, a nd just befor e descend ing it good vie ws are to be had over t he Gault va lley a nd Lower Gre ensand hill as far as Hindh ead to t he west and over Lei th H ill, to the ea st. P assin g on th rough t he beau tifull y wooded district of t he King's ' Voods, t he s um mit of t he Chalk was r eac hed. H ero t he Ridgeway R oad, a wid e open grass g lade stretc hi ng for mil es east an d west , was crossed, and woods again ent er ed. As the descen t of the northern dip-slope of the Cha lk began , the pa th ra n throug h a pl antation of finely-gro\Yn beech es, down to H oneysu ckl e Bottom, which is skir ted on t he west by a plant ati on of fir t rees, known as Mou nta in Wood. At the northern end of t his wood a halt was made, and us the party rested und er t he shade of t he trees, the Director expla ined a change wh ich th e oflicers of the Survey had found necessary in th e mapping of the
EXCURSION TO GOMSHALL, NETLEY HEATH, AND CLANDON.
183
The alteration related to the extent geology of the district. of ground covered by the large tertiary outlier on N etley Heath. As marked, it extended too far east and south. On re-examination it had been found to cover about one-third only of the space at present shown on the map, and to consist of three detached outliers; the largest in Hook \V ood, with a smaller in Barnet "Vood to tl.o south-west, and a third small patch at Pobley Farm to the north-east. A considerable stretch of "Sands of Doubtful Age" would be marked resting on the Chalk and occupying the area of the rest of the outlier, as at l)resent mapped, extending beyond it south and eastwards nearly as far as Green Dene Farm. The main feature of this visit was to see exposures of these sands, of gravel and associated beds in Hook IV oorl , and the well ut Clundon. Patches of these" Sands" occur along the North Downs from Folkestone to this, their present most westerly known extension. '1'0 what formation they belong has long been debated without any generally accepted solution lHlving been arri vod at. In Professor Prestwich's paper" On the Sands and Iron Sandstones of the North Downs," in 'Q.J.G.S.,' Vol. xiv (1858), pp. 321335, they are claimed as the equivalents of the lowermost (Coralline Crag) beds of the Pliocene of East Anglia. Mr. Whitaker, writing in 1871 on "The Geology of the London Basin" (' Geol. Surv. Menl.,' Vol. iv , Part 1, pp. 336-342), is inclined to place them low down in the Eocenes as overlapping masses of the Woolwich and Oldhaven series. So the question rested until last year, when Mr. Clement Reid published in u: N atui-e " (l2th Aug., 1886) tlte result of his investigation of the beds at Lenham, which thoroughly corroborates Professor Prestwich's view. Speaking of the fossil evidence, Mr. Reid sa,ys: "Thel'e is not a, single Eocene species among them. With two or three exceptions they are all known Pliocene forms, some are new to England, though occurring in France and Italy." The Crag age of the Lenham Beds may now be regarded as established. Professor Prestwich is of opinion that the other patches of Sands of the North Downs, though they differ in character from the Lenham Beds, are all of the same age. As none of them have yielded fossils, the conclusion must be received with some reserve, although other considerations tend to confirm t his view, The position of these
184
EX CURSION TO GOMBHAI ,I" NF.TLEY HF:ATH , AND CI, ANDO l,-
beds, on the summit of t he Chalk Downs, 600 feet above sealevel, indicates t hat t he great va lley of the ·Weald has been excavate d since Pliocene ti mes, t he S ands ha ving , in all pr obability, been derived from t he denudation of a Lower Gre ensand island which ex iste d wh ere the Wealden valley now is. -The following sections were t hen examined : I .-Band.p it B. W. of F ir P lantation ( near R.M., 591-2 on 6in. Ordnance M ap) . 1. Brick-earth , r eplaced in parts by mot tl ed clay, flint gravel, and san d. pocketin g irregularly into t he und erlying sanda, shallow bands of sub-angular flints and p ebbles. frequent at th e ju nction... From Oft. Oin, t o 4ft. Oin. 2. Yellow-brown ferruginous sands, apparent ly false-bedded... Seen to 6ft. 6in.
This section showed that the sands were of earlier date than the "drift," and lat er than the Lower Tertiaries, which occur within half a mil e of the pit and differ from t hem in colour and lithological cha raeter . In r eply to Rev. A . Irving, wh o claimed t hem as B agsh ots, it was pointed out t hat th ey occur re d at a lower level th an th e Tertiaries of t he dist ri ct , an d as the London Clay was believed to be present in B arn et W ood (wit hi n t hre e-quarters of a mil e west, at an elevat ion of 674 feet ) , t he suggestion would imply considerable cont emp orane ous erosion. In t he abse nce of fossil evidence, it was impossibl e to det ermin e t heir age within t he ab ove limit s j but r egar ding them as the equivalents of t he Lenham Beds they would be classed as Crag. I Io-Pit N .W. end of Fir Plantation, about 540ft. above 1. Cappi ng of soil ... 2. Bro wn cla yey sand enclosing t wo irregul ar mas ses (4f t. x lift . and Skft . x IHt.) of red-blu e mould clay (apparently derived fr om Woolwich and Reading beds) 3. Ochreous sands ...
Ordnance Datum. a fe w inches.
1 t o 6 feet . ju st seen.
'I'he excavation is not sufficient ly deep to allow of t he connection between Beds 2 and ;j being made out with certainty, but Bed 2 appears to cnt and pocket into Bed 3. Bed 2, on the other side of t he pit, contains rounded flint pebbles and" pebbles" of cha lk, some of the latter being Bin, long, though gen erally smaller.
EXOURSION TO OOMSHAJ,f,. NETLEY HEATH, ANn CLANDON.
185
III.-Gravel Pit on summit of hill in Hook Wood, on road from Woodeote Lodge to Fuller's Farm, about 678ft. above Ordnance Datum. 1. Capping of mottled clay, sand, and flint
2. 3.
4.
S. 6.
gravel, irregularly mixed up, and in more or less wavy lines Irregularly waved band of gravel cutting into under. lying bed Compact clay (?brickearth) with small broken angular pieces of white flint and a few" nodules" of chalk 6in.long ... Gravel composed of small (white) well-rounded .flint pebbles, with a large admixture (disseminated through the mass) of medium-sized and very large water-worn flints Hard brown clayey sand Gravel alternating with light-coloured sand," much obscured by talus. The limits of each division consequently undeterminable
6ft. From lin. to Ift,
3ft. 6in.
3ft.6in. 1ft.Oin.
About 6ft.
Skirting Hook Wood, a small exposure of Woolwich and Reading Beds was seen in a pond at Fuller's Farm. Continuing round Barnet Wood, where mottled clay is to be seen, Merrow Downs were crossed, whence fine views across the Thames Valley are obtained when the atmosphere is clear, and Clandon was reached in time to view the spoil-heaps of the well which has been sunk for the W oking Waterworks Company. By the courtesy of the contractors, Messrs. Quill, we are enabled to give the following sections from particulars supplied by their foreman, Mr. Langton, who kept a most careful diary of the strata passed through as the work proceeded. IV.-Section of Clandon Welt (Woking Waterioorlcs Company).
1. Soil 2. Flints and yellow loamy clay 3. BLUE (LONDON) CLAY... Thirteen bands of Septaria were passed through the nodules measured more than Sft. across.) Black loamy sand and a little water A few pebbles and a little water Traces of sand Veins of sand with water Veins of sand with water Veins of sand Reddish clay Few shells... Basement bed, well-rounded black pebbles
2ft. Oin. Sft. Oin, 224ft. Oin, (some of at 30ft. \
I""'
at 121ft. at 133ft. ~. at 138ft. I .£ ~~ ~ Q) " at 143ft. I o::l III at 203ft. s o::l at 215ft. ~ at 219ft. ... Oft. nin .
I
J
.. The sands are well seen iu rabbit-holes on the south side of hill.
186
EXCUHSION TO GOMSHALL, NETLEY HEATH, AND CLANDON.
4. WooT,wIeR AND R~ADING BRDS Compact bed of shells and clay ... Compact bed of sbells and limestone Mottled clay, blue and brown Do. red and bluish Do. brown and blue Do. buff and brown Do. light blue and red . Very dark clay, spotted brown . Mottled clay, red and buff Do. pinky-red and slate Very hard Iight-blne clay Pink and light-blue clay ... Mottled clay, becoming sandy towards base
*
Hard loamy Greensand . Hard grey yellow sand . Sandy green loam mottled brown Hard Greensand, dry and loamy, with scattered shells, much broken ... Thin bed of small well-rounded dark flint pebbles Greenish loamy clayey sand Clean grey sand full of water Green-coated flints
1 ft.l 11ft. ) 3 ft., 1 ft. 2 ft. 4 ft. 4 ft., 9 ft 5 ft: 1 ft. 2 ft.
r
83ft.
Oin,
314ft.
6in.
66ft.
4~ft.
30~ft.J 2!ft'l L,ft. I
To Chalk
ff
t·l
41 ft .
~
14~ft.
Ut.)
2ft. 2ft. I
¥t.J
REFERENCES. Geological Survey Map, Sheet 8. Ordnance Survey :Map, new series, Sheet 285. WBITAKF:R.-" Geology of the London Babin" (' Melli. Geo1. Snrv.,' Vol. iv), " At tbe deptb of 2(j9~ft. the diary was discontinued, but was resumed agaiu at 300ft. When the well was first dug, water rose and overflowed to 10ft. above the surface of the ground.