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IV.—Note on the Source of the Pebbles of the Bunter Pebble-beds of the English Midlands

Published online by Cambridge University Press:  01 May 2009

C. A. Matley
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Extract

The subject of the derivation of the materials which form the Bunter Pebble-beds has given rise to wide differences of opinion and to a voluminous literature. These it is not my intention to recapitulate, as an excellent summary of the subject will be found in Mr. O. H. Shrubsole's paper of 1903. Mr. Shrubsole then gathered together the known evidence, added some new facts of his own, and came to the conclusion that the Midland Bunter pebbles were brought from a southerly direction. This opinion may be said to have held the field until recently, when the question was again taken up by Mr. Jukes-Browne in the third edition of The Building of the British Isles (1911). After reviewing the whole evidence and taking into consideration the results of an investigation by Mr. E. C. Martin, which tended to show that the direction of transportation in Somersetshire in Bunter times was towards the south, Mr. Jukes-Browne abandoned the view he had taken in the second edition (1892) of that work, and now, adopting in the main the conclusions of Professor Bonney, considers that the bulk of the pebbles of the Midland Bunter came from the north-west, though he agrees that the fossiliferous quartzite pebbles could not have come from that direction, and he suggests for these a south-easterly derivation (Suffolk).

Type
Original Articles
Information
Geological Magazine , Volume 1 , Issue 5 , May 1914 , pp. 211 - 215
Copyright
Copyright © Cambridge University Press 1914

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References

page 211 note 1 “On the Probable Source of some of the Pebbles of the Triassic Pebble-beds of South Devon and of the Midland Counties”: Q.J.G.S., vol. lix, pp. 311–31, 1903.

page 212 note 1 Except in the discussion on Salter's, A. E. Dr. paper “On the occurrence of Pebbles of Schorl-rock from the South-west of England in the Drift Deposits of Southern and Eastern England”: Q.J.G.S., vol. lv, pp. 220–3, 1899.CrossRefGoogle Scholar

page 215 note 1 It is true that Spirifer verneuili was found in the Tottenham Court Road boring, but it is a widely distributed Devonian fossil, and it occurred there in a matrix altogether different from the Bunter pebble type.

page 215 note 2 I have not seen the specimens, but I would be inclined to eliminate from the published lists of fossils found in Drift pebbles and ascribed to the Bunter those that indicate a Llandovery age. For instance, Stricklandinia lirata in W. J. Harrison's list is found in the Rubery Sandstone of the Lickey Hills. This sandstone is made up of the waste of the Lickey Quartzite, on which it rests unconformably, and it sometimes simulates in texture and appearance the older rock. Specimens from this source may have come direct into the Drift without ever having become Bunter pebbles, and in either case they are of local origin.

page 215 note 3 The less-rounded quartzite pebbles of the Lower Keuper basement-beds of the Midlands suggest a derivation from local quartzites. The materials of these beds, as Mr. Harrison remarked in 1882, deserve careful and detailed study.