Difference between revisions of "Excursion to the North, Downs near Marden Park. Saturday, September 26th, 1914 - Geologists' Association excursion"

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Geologists' Association Circular No. 170. Session 1913-1914. p.4-5[edit]

Excursion to the North Downs, near Marden Park. Saturday, September 26th, 1914 (Transcription from: Circular No. 170. Session 1913-1914. p.4-5)[edit]

DIRECTORS: W. WHITAKER F.R.S. and C. C. FAGG.

EXCURSION SECRETARY: A. H. WILLIAMS, 13, Derwent Villas, Whetstone, N.

Meet Mr. Williams at London Bridge (L. B. S.C.R.) not later than 1.10. to obtain cheap tickets, price 2s. 3d. Train leaves at 1.25 p.m. Arrives at Woldingham at 2.19 p.m.

Walk southward through Marden Park. to the top of the escarpment at Chaldon Farm (marked Tandridge Hill on the old Ordnance Map), just southward of which pits have been opened in the:Blackheath Pebble-beds, at the edge of the escarpment and at a height of about 770 ft above O.D. They are notable as containing a great many unrolled flints, of fair size, in patches, and these cannot have got in by the same process as the well-rolled pebbles.

There is an old pit westward of the farm, which may also be visited. Probably the pebbles extend slightly further than is shown on the old Geological Survey Map.

The walk wid then be continued down the eF-:carpment, here largely wooded, to "Nixon's Pit" of the six-inch map (Surrey 27), an old chalk-pit in the wood.

Just westward of this, and at about the 600 ft. contour, Mr. Fagg lately found a new section, of much interest, and which is the objective of the excursion. It shows some 30 ft. of the Blackheath Pebble-beds, near the foot of the Chalk-escarpment, either on Lower Chalk or on the lower part of the Middle Chalk, a thing that has never been seen before.

Here, again, there are very many unrolled flints, as well as the well-rolled pebbles; the raw material and the finished article, but without any connecting link.

At the southern and lower part of the pit a shallow section shows the junction of the Tertiary beds with the Chalk; but between the pebbles and the latter there is some greenish-grey clayey earth, with some of a reddish tint, more or less bedded and up to 3 ft. thick. This is suggestive of the base-bed of the Thanet Sand; but a reddish layer has been recorded in this only in one place in Surrey, and the usual green-coated flints were not noticed.

As to the pebble-beds there can be no doubt what they are the section is like many sections in undoubted Blackheath Beds; but the question is, flow did they get into such a place ? To this a goodly number of answers has already been provided, and it is hoped to get more from the party.

The walk. will be continued southward, and pebbly patches (wash) on the Gault may be seen, the leavings of a former extension or the Blackheath Beds. Then the Folkestone Beds will be reached, and seen, and an easterly turn will take the party to Oxted, where tea will be had near the station.

Return by 7.0 p.m, train from Oxted. Arrive London Bridge 7 p.m.

REFERENCES.

Ordnance Map, Sheet 286 New Series.

Geological Survey Map, Sheet 6, Surrey, Sheets 27, N.E. and S.E.

Images[edit]

Excursion to North Downs near Marden Park, September 26th 1914[edit]

List of photographs[edit]

Excursion to North Downs near Marden Park, September 26th 1914[edit]

Page 75 P804774 Blackheath Pebble Beds at 790 feet OD. Chaldon Farm, Pit A. Excursion to North Downs near Marden Park, September 26th 1914. Here at the Caterham outlier there are many large angular flints, mostly but little broken and which clearly have not been carried far, collected together in patches.
Page 75 P804775 Blackheath Pebble Beds at 770 feet OD. B or Middle Pit, SSW of Chaldon Farm, a mass of sandy pebble beds with nests of large unrolled flints. . Excursion to North Downs near Marden Park, September 26th 1914.
Page 75 P804776 Blackheath Pebble Beds. C or Hanging Wood Pit below than 700 ft. OD. Excursion to North Downs near Marden Park, September 26th 1914. This is a deeper section in the same beds but a pinnacle of chalk is seen with clayey material next to it. This corresponds with that seen at Worms Heath in 1910. Added note: Pinnacle of chalk.
Page 75 P804777 Blackheath Pebble Beds. C or Hanging Wood Pit below than 700 ft. OD. Excursion to North Downs near Marden Park, September 26th 1914. This is a deeper section in the same beds but a pinnacle of chalk is seen with clayey material next to it. This corresponds with that seen at Worms Heath in 1910.
Page 77 P804778 D Pit at 600 OD ? 30 feet of Blackheath Pebble Beds near the foot of the chalk escarpment. Excursion to North Downs near Marden Park, September 26th 1914. At the entrance of this pit on the south the chalk is seen below the pebble beds, between which is a clayey earth of a greenish tinge somewhat suggestive of the base bed of the Thanet Sand.
Page 77 P804779 D Pit at 600 OD ? 30 feet of Blackheath Pebble Beds near the foot of the chalk escarpment. Excursion to North Downs near Marden Park, September 26th 1914. At the entrance of this pit on the south the chalk is seen below the pebble beds, between which is a clayey earth of a greenish tinge somewhat suggestive of the base bed of the Thanet Sand.
Page 77 P804780 Here are many unrolled flints as well as well rolled pebbles, but no sub-angular pieces. . Excursion to North Downs near Marden Park, September 26th 1914.
Page 77 P804781 Blackheath Pebble Beds. Excursion to North Downs near Marden Park, September 26th 1914. It is only in these outliers where the pebble beds have cut across well over the flinty chalk that the unrolled flints occur. Where the Blackheath Beds are separated from the chalk by Woolwich and Thanet Beds, no unrolled flints are found.