Vol. 56.] THE BUNTER PEBBLE-BEDS OF THE MIDLANDS. 301 



expected, may exist, the dominant characters of the pebbles are 

 unchanged. They must have been transported by a large river, or 

 probably two (I regard the Devon pebble-beds as the delta of a 

 third river), flowing with a current, the rate of which, when the 

 pebbles were being moved, varied from 2 to 3 miles an hour, 

 Such rivers cannot issue from limited tracts of land. We have now 

 no English streams capable of producing the Bunter Pebble-beds, 

 Their feeding-ground must either have been very large — continental, 

 not insular in character — or the rainfall upon it must have been 

 exceptionally heavy. 



"What evidence is there that any such region existed to the 

 immediate east or south of the Midlands ? None that I can find, 

 but very much to the contrary. This, however, is not all ; the 

 Bunter pebbles imply, not only a large and strong stream, but also 

 a long journey. Daubre'e's well-known experiment showed that to 

 round an angular fragment of a hard rock, such as a quartzite, into 

 a pebble required a journey of nearly 16 miles. This, however, 

 must be taken as only a minimum distance, for he subjected his 

 materials to conditions which resemble those existing in an Alpine 

 torrent, rather than in an ordinary strong stream. In the Alpine 

 rivers, as I have shown, the pebbles, though the majority must have 

 travelled from 30 to 60 miles and the materials are commonly 

 softer than quartzite, are not usually so well rounded as those in 

 the Bunter. 1 



Thus, on physical as well as petrological grounds, all those 

 insignificant outcrops in the Midlands, even allowing them some 

 enlargement — the hidden isthmus between Gloucestershire and 

 Devon, the buried plateau under our eastern and south-eastern 

 counties— are ruled out as inadequate; they, as a little study of a 

 geological map, or of that appended (p. 300), will show, could not 

 have given rise to streams of sufficient size and potency, unless we 

 suppose the Bunter to have been a ' pluvial epoch.' 



The hypothesis of a northward How of the water, which evidently 

 is favoured by Mr. Jukes-Browne, 2 lands us in more than one difficulty 

 if we admit, as we are compelled to do, the river or rivers to have 

 been large. Suppose for a moment the Bunter-beds in the circum- 

 Pennine region to have been deposited by a stream which came 

 from Devon, or from somewhere towards the south. If so, it 

 was bifurcated by the Pennine range, which must have been a kind 

 of promontory from a large mass of land to the north. Such bifur- 

 cation is not, perhaps, impossible, but it is unusual, and wants 

 more foundation than an hypothesis. But, conceding the possibility, 

 I ask — What became of the river ?, for evidently it did not produce 

 an inland sea till Keuper times. I have identified pebbles of 

 Bunter quartzites and one or two of felstone, with plenty of vein- 



1 The evidence is given, and the applicability of the results to the Bunter 

 indicated, in a paper ' On the Bounding of Pebbles by Alpine Rivers, etc' GeoL 

 Mag. 1888, p. 54. It is a curious fact that this paper has been ignored by the 

 advocates of an 'adjacent ' origin. 



2 ' Building of the Brit. Is.' 2nd ed. (1892) p. 192. 



Q. J. G. S. No. 222. t 



