Excursion to Virginia Water and Chertsey. Saturday, April 12th, 1913 - Geologists' Association excursion

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Geologists' Association Circular No. 154. Session 1912-1913. p.3-5.

Excursion to Virginia Water and Chertsey. Saturday, April 12th, 1913. (Transcription of: Geologists' Association Circular No. 154. Session 1912-1913. p.3-5.)

DIRECTOR: C. E. N. BROMEHEAD, B.A. F.G.S.

EXCURSION SECRETARY: T. W. READER 17, Gloucester Road, Finsbury Park. N.

Leave Waterloo 1.10; arrive Virginia Water 1.59. Special return fare, 2s. 3d. each, Meet in booking office not later than 12.55.

The primary object of this excursion is the study of a diversion of the Bourne, and the process by which it has been brought about. The Bourne, which drains Virginia Water Lake, formerly pursued a south-easterly course to the Wey. Its ancient valley, now dry, is a continuation of the upper part of the existing course, and is occupied by gravels which form a single series with those occurring as terraces above the point of diversion. These gravels are at two levels, and can be correlated with the 100 ft. (Boyn Hill) and 50 ft. (Taplow) terraces of the Thames. Bourne was formerly separated from the Thames by a. ridge of Tertiary strata, of Callow Hill, St. Ann's Hill, and Woburn Hill are relics. The post-Taplow erosion by the main river broke through this ridge and the Bourne was diverted and now finds an exit near Trumps Mill to the Thames flood-plain.

Walk from Virginia Water Station northwards to a pit in Great Wood, where the Bagsbot Pebble Bed is well exposed. Thence to Trumps Mill, near which a view down the old course of the Bourne, cut across in the foreground by the existing stream, can be obtained. Cross the gorge and walk to Lyne Grove, where is a pit in the gravels of the 100 ft. terrace. Continue walk along deserted valley to St. Ann's Hill, which conarnands a magnificent: view of the Thames Valley and surrounding country. The summit of the hill consists Bracklesham Clays with a strong pebble bed. If time allows see also extensive sections of the Bagshot and at the base of the hill.

Walk on to Chertsey ; tea at Crown Hotel, 1s. each, With eggs, 1s. 3d.; return to Waterloo from Cherisey Station at 6.25 or 6.38, arriving 7.24 and 7.47 respectively.

Walking distance about 6 miles.

Several of the sections and landscape views are worth photographing.

Figure 2—Geological Map of the Bourne Valley. Scale, three inches = 2 miles. (Reproduced from: "Summary of progress of Geological Survey for 1911" by permission of H.M. Staionery Office.)

REFERENCES.

Maps, 1 in., Geological Survey, London District, Sheet 3, Price 1s. 6d. Old Series Maps, Sheet 8 (Drift).

Ordnance Maps, 1 in., Small Series, Sheet 269 (Windsor). Large Series, Sheet 115.

1872. HAWKINS, C. E., in Mem. Geol. Surv, vol. iv, p. 315.

1909. WOODWARD, H. B.—"Geology of London District." 'Mem. Geol. Surv., p, 43. Price 1s.

1912. BROMEHEAD, C. N.—"On Diversions of the Bourne near Chertsey " (with map), in "Summary of Progress of Geological Survey for 1911." Price 1s.

Images

Excursion to Virginia Water and Chertsey. Saturday, April 12th, 1913

List of photographs

Excursion to Virginia Water and Chertsey. Saturday, April 12th, 1913

Page 13 P804529 Bagshot Pebble Bed in pit in Great Wood north of Virginia Water Station. Excursion to Chertsey, April 12th 1913.
Page 13 P804530 Bagshot Pebble Bed in pit in Great Wood north of Virginia Water Station. Excursion to Chertsey, April 12th 1913.