430 



P. B. BRODIE ON CERTAIN QTJARTZITE AND SANDSTONE 



34. On certain Qtjartzite and Sandstone Fossiliferotts Pebbles in 

 the Drift in Warwickshire, and their probable Identity, liiho- 

 logically and zoologically, with the true Lower Silurian Pebbles 

 with similar Fossils in the Trias at Bttdleigh Salterton, 

 Devonshire. By the Rev. P. B. Brodie, M.A., F.G.S. (Head 

 May 11, 1881.) 



Special interest and some little difficulty attaches to the history 

 and origin of certain quartzite and other pebbles in the Drift in a 

 limited portion of the Midland Counties, which it is desirable, if 

 possible, to determine. With this object I beg leave to lay a few 

 more additional particulars before the Society, which will form a 

 supplement to my previous paper in the Quarterly Journal, vol. xxiii. 

 p. 210, 1867. It seems probable that the Keuper sandstones and 

 marls in the more central parts of England were at one time much 

 thicker, before denudation had reduced them, and that the pebble- 

 beds existed in them as at Budleigh Salterton, and were afterwards 

 broken up and the pebbles (like the flints of the Chalk) scattered 

 about in all directions by powerful currents of water, helping to 

 form a large proportion of the Drift in this and other parts of the 

 Midlands. In a short notice in the Geological Magazine (July 

 1878), Mr. S. G. Percival supposes that the quartzose and many 

 other pebbles in the Drift of the Midland Counties were originally 

 derived from the Bunter conglomerate. This may be probable in 

 some slight degree ; and Mr. Jennings, in the Geological Magazine 

 (May 1878, No. 167), states that he has found Orthis redux (bud- 

 leighensis) in a supposed Bunter pebble near Nottingham, where a 

 careful search should be made for other fossils which may occur 

 there in situ, both in the Conglomerate and the Drift — viz. the 

 gigantic Lingidce so characteristic of the lower Silurians in Nor- 

 mandy, some of which I have already detected in the Drift at 

 Rowington. If it can be shown that these pebbles in the Drift were 

 originally derived from the Bunter, the latter must have been 

 broken up before they were deposited in this newer portion of the 

 Trias ; then comes the question, Whence were these pebbles derived 

 in the first instance, before they were washed, first into the Bunter 

 (helping to form the Conglomerate), and afterwards into the later 

 New Red Sandstone, as they certainly were, in Devonshire and 

 other places ? 



The fossils found in these pebbles here and elsewhere show 

 that many belonged to Palaeozoic rocks, as evidenced by Orthis 

 budleighensis, Lingida Leseurii, Trachyderma serrata, and some 

 others given in the list at the end of this paper. Some of these, 

 especially the Lingidaz, are species which as yet have not been 

 noticed anywhere in situ in this country, but are peculiar to Nor- 

 mandy and Brittany, and were determined by the late Mr. Salter. 

 Mr. Pengelly (Geol. Mag. No. 167, 1878) thinks that the occurrence 



