Excursion to Guildford. June 25th, 1877 - Geologists' Association excursion

From: A record of excursions made between 1860 and 1890. Edited by Thomas Vincent Holmes , F.G.S. and C. Davies Sherborn, F.G.S. London: Edward Stanford [For the Geologists’ Association], 1891. Source: Cornell University copy on the Internet Archive (Public domain work)

Director: R. A. C. Godwin-Austen, F.R.S. (Report By C. J. A. Meyer, F.G.S.) (Proc. Vol. v. p. 161.)

Note: [Guildford was first visited by the Association in 1869, during the cessation of issue of Proceedings. From a brief record of the event in the Geol. Mag. for 1869, p. 331, we learn that the chief object in view was "the examination of the several kinds of strata forming the hills and vales in the vicinity of Guildford, Mallard, and Chilworth." The leaders were the President (Prof. Morris), C. J. A. Meyer, and Prof. T. Rupert Jones. The second excursion was in 1872.]

On this occasion members assembled at Chilworth Station. After a few words as to the proposed course of the excursion from the Director they proceeded to examine a bed of Elephant gravel exposed in a new road-cutting. This gravel, which formed an eastern extension of the Peasemarsh valley-gravel, was observed to consist largely of unrolled and broken flints, mingled with fragments of the Bargate stone, Chert, and Carstone (Ironstone), of the Lower Greensand. It contained apparently neither rounded flints nor flint pebbles. The gravel rested here on Hythe beds; further westward it covered both Atherfield Clay and Weald Clay.

The Tillingbourne stream, which was prese9tly crossed on the way towards St. Martha's Hill, was described as running partly on the Weald Clay and partly on the Atherfield Clay, or lowest member of the Surrey Greensand. At the foot of St. Martha's Hill the party separated into two groups—one with Prof. Morris, taking the shortest path to the hill-top; the other, under Mr. Godwin-Austen, taking a lodger route, with the chance of finer sections. At the top of St. Martha's, and while waiting for the re-union of the party, Mr. Meyer described briefly to those present the succession of the strata included in the Surrey Greensand. On mounting the hill they had passed over in succession the outcrop of the Atherfield Clay, Hythe beds; Sandgate beds, and Folkestone beds of the Lower Greensand. The Atherfield Clay (first noticed in England by Godwin-Austen in 1843) is here very rich in fossils in its lowest beds, which are most unfortunately, however, very rarely exposed. The Hythe beds and Sandgate beds exhibit by comparison a singular dearth of fossils — Exogyra sinuata, Hinnites Leymerii, Terebratula sella, an Ammonite or two, and a species of Belemnite, probably completing the list of those obtainable in this district. The pebble-bed and Bargate stone series, forming the base of the Folkestone beds, contains a fauna, remarkable chiefly for its wide range, and from its differing so entirely in this district from that of the lower beds. The ferruginous sand, with Carstone capping the hill on which they stood, was wholly unfossiliferous. This sand-bed had here a thickness of about 130 feet. In the Isle of Wight, where it was also unfossiliferous, its thickness was even greater. At Folkestone, curiously enough, it was almost entirely absent; its position being there held by a detrital bed of about one foot in thickness.

Turning now towards Guildford the Warren Farm Section of highly inclined Grey Chalk and Chalk Marl was next visited; specimens of Nautilus elegans, Terebratula obesa, and Inoceramus rewarding the search for fossils. The two Chalk pits in Quarry Street were also briefly visited. The lowest of these contains but few fossils only of the zones of Inoceramus labiatus, Terebratulina gracilis, and Holaster planus. The larger and higher quarry embraces a section displaying the zones of Holaster planus, Micraster cor-bovis, and M. Desori (?); and, in great force, the zone of Micraster cor-testuclinarium, with many of the associated fossils. Sponges and cone-like pressure-striated concretions abound in both quarries on certain limited horizons.

On reaching Guildford the members took carriages for the drive to Seale Rectory, near Farnham, the course taken being along the top of the Hogsback. It was interesting to observe the subtle differences in outline and fertility of the country to north and south of this dividing ridge of Chalk.