Excursion to Maidstone. April 2nd, 1872 - Geologists' Association excursion

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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)


Note: [An "Excursion to the Medway Valley from Maidstone to Aylesford" took place on July 14th, 1883, J. Logan Lobley being Director. An account of the route taken, and sections visited, may be seen in Proc., vol. viii. pp. 192-4. Mr. Lobley refrained from giving full details on account of the existence of three other reports of excursions to this locality.]

Note: [Maidstone was one of the three places visited by the Association during 1860 (June 19th), the first year during which any excursions took place. There is a brief report of it in Proc., vol i., pp. 63-4. The party was under the guidance of the Rev. T. Wiltshire, who was theft President, Prof. Tennant, and Mr. Bensted. The Iguanodon Quarry and the Charles Museum were first inspected, and the party thence proceeded to Kits Coty House and Aylesford, visiting the pit in River Drift, which is fully described in the report of the Excursion to the Gorge of the Medway, on a previous page. The next excursion to Maidstone was on April 2nd, 1872, from the report of which the following details are extracted.]

Excursion to Maidstone. April 2nd, 1872

Directors: Professor T. Rupert Jones, F.R.S.; Professor Tennant, F.G.S.; and W. H. Bensted. (Proc. Vol. iii. p. 38.)

On arriving at Maidstone, the party was met by Mr. W. Bensted, jun., and conducted to the "Charles Museum," the free public museum of the town, in a fine old manor house. Many of the rooms are filled with a miscellaneous collection of antiquities, pictures, and other objects of general interest, amongst which may be specially mentioned a valuable collection of Saxon weapons, utensils, and ornaments, found at Sarre, near Canterbury. In the old picture-gallery is a collection of fossils, and conspicuous among these are some beautiful Chalk fish-remains, from Barham Downs, near Maidstone. These are chiefly of the genus Beryx, with one or two specimens of Dercetis elongatus. In a small upper room is a collection which gives a special value to the Maidstone museum, consisting of the vegetable remains found in the Lower Greensand of the neighbourhood of Maidstone, collected during many years by Mr. Bensted.

The following species, amongst others, are here represented :— Endogenites erosa, the leaves of a cycadean plant (Clathrarta), Dracæna Benstedi, and the fragment of a dicotyledon bored by a mollusc, and misnamed Stigmaria.

After luncheon the party proceeded to the well-known Iguanodon Quarry, from which Mr. Bensted obtained the specimen described by Mantell, and now in the British Museum. The quarry in which this valuable fossil was found is not now worked, and the sections are obscured by débris. There is, however, in the quarry a ridge which may easily be mistaken for a mound of rubbish deposited by the quarrymen, but which is of far more ancient origin, since it is no other than the Post Pliocene infilling of a great fissure in the Lower Greensand. The rock having been removed on either side by the operations of the quarrymen, the mass filling the fissure has been left as a dyke-like. ridge. It consists of argillaceous matter, and " gravel composed of angular broken Chalk flints, flint pebbles, subangular fragments of the Hastings Sandstone, and a few pieces of ironstone from the same beds, with angular chert, and, rarely, quartz pebbles." (Bensted, Proc. Geol. Assoc. vol. 1, No. 5, p. 58).

In the fragments of ragstone lying about the quarry were found numerous specimens of Molluskite. This name was given by Dr. Mantell to certain small, dark-coloured masses, believed by that author to owe their origin to the animal matter of molluscs.

At a short distance from this interesting quarry, a point is gained from which an extensive view is obtained, embracing a considerable portion of the valley of the Medway, and the geological structure of this part of Kent is distinctly seen.

An extensive quarry belonging to Mr. Bensted was next visited, and the Kentish Rag well seen. This valuable building stone is a tough, bluish limestone, occurring in layers of from a foot to three feet in thickness, and alternating with beds of a soft, sandy stone called hassock. Some of the best of the ragstone contains 90 per cent. of carbonate of lime, while the hassock has but ten or twelve per cent. The amount of ragstone quarried in the neighbourhood of Maidstone is very great, Mr. Bensted alone sending away nearly 1,000 tons weekly. This rapid removal of the rock has been going on for centuries; most of the ancient churches and castles of Kent being constructed of this material, and so ancient a building as the White Tower of London is partly built of Kentish rag. Two blocks of the ragstone, lying at the bottom of the quarry, on being split, showed faces covered, in the one case with Trigonia alæformis, and in the other with this species and Gervillia anceps.

Associated with the rag is a considerable quantity of chert, containing spiculm of sponges. Fossil wood is often found in these beds, and some of this is bored. Leaving the ragstone quarries, a path following the course of the river was taken. At a little distance in this direction there is a tramway to the river bank through an old quarry, in which are seen as many as twelve of the dyke-like ridges, one of which was observed in the Iguanodon Quarry. These, the infillings of fissures in the Lower Greensand, are parallel to each other and to the river valley. The argillaceous earth of which they are largely composed is a good brick-making material.

After passing the interesting and picturesque ruin of Allington Castle, the river was crossed at Allington Lock, and the village of Aylesford was soon reached. Near this village a very fine section is exposed. (See Excursion to the Gorge of the Medway, p. 52.)

[The third excursion to Maidstone was on July 10th, 1880, Professor J. Morris being Director. The party visited the Charles Museum, the Iguanodon Quarry, the Preston Hill Quarries, and the Aylesford Post Pliocene deposits. (See Proc., vol. vii. p. 392). Another excursion was made July 10th, 1886. Of this a full report by the Director, Professor Boulger, may be seen in Proc.,vol. ix., No. 8, 1 p. 551-4 ]

References

Maps

Ordnance Survey. Geological. Sheet 6. 8s. 6d. New Ordnance Survey. Sheets 272, 288. 1s. each.

Books

W. Topley, Geology of the Weald, 8vo, London, (Geol. Survey), 1875. 2 8s.

W. H. Bensted, Geologist, vol. iv. 0860, p. 2.21; vol. v. (1862), pp. 294, 334, 378, 44/-.

W. H. Bensted, On the Kentish Ragstone, as exhibited in the Iguanodon Quarry at Maidstone, Proc. Geol.. Assoc., vol. i. (1860), pp. 57-60.