Vol. 56.] BUNTER PEBBLE-BEDS OF THE MIDLANDS. 289 



to enumerate briefly all the principal varieties. Vein-quartz and 

 quartzites are the most abundant. The former are usually white, 

 and very rarely they include black tourmaline, which in one 

 specimen forms a tufted group of acicular crystals, nearly ^ inch 

 across. 1 Some varieties are cellular, and show miuutely crystalline 

 quartz ; some are more chalcedonic in texture (one of them tinted 

 green in places, probably by malachite). Another set, apparently 

 connected with friction-breccias, will be more conveniently noticed 

 later on. 



Of the quartzites little more need be said. The cementation 

 is so perfect that the individual grains are often difficult to see 

 with the unaided eye, and the fracture is sometimes subconchoidal. 2 

 The colours vary, ranging from almost white — a pale buff or grey — 

 to a dark tint, and (seldom) a greenish-grey ; others are a dull red, 

 light to fairly dark, and the characteristic ' liver-coloured ' variety 

 is not rare. These quartzites sometimes are speckled with frag- 

 ments of red felspar, and thus graduate into the finer varieties of 

 the quartz- felspar grits. The latter are generally uniform in 

 grain, but occasionally more irregular. They vary from fine to 

 Tather coarse, and, as already said, exactly resemble the Torridon 

 Sandstone of the North-western Highlands. 3 



Pebbly quartzites are found, the pebbles being usually vein- 

 quartz, the matrix often rather dark. Besides these, grits of 

 various kinds are fairly common, varying from quartzites to hard 

 sandstone. One or two remind me of pebbles from the Permian 

 of Leicestershire, which have been described by Mr. H. T. Brown, 

 F.K.S. 4 Some are banded, and may perhaps belong to the group 

 already described. Others, often reddish, might come from Ordo- 

 vician, Silurian, or even later systems. 



Fossiliferous pebbles are not common. In the true quartz- 

 ites I have seen only worm-tubes, and these in about four 

 specimens ; from the grits I have collected, since 1883, three with 

 other organic remains, but for these pebbles I have not specially 

 sought, as they have already received considerable attention. As, 

 however, it seemed very desirable that the identification of the 

 fossils should be authoritative, I availed myself of the kindness of 

 Mr. E. T. Newton, F.R.S., who has sent me the following notes : — 

 A (A) Orthis budleighensis, Orthis sp., and a trilobite-fragment. 

 B (1) Atrypa reticularis ; (2) internal cast, probably Atrypa ; 

 (3 & 4) Euomphalus? ; (5) Strophomena sp. ; (6) Favosites sp. ; 

 (7) turbinate coral ; (8) Cornulites serpularius. (C) In two pieces ; 

 cast of branching coral, probably Alveolites repens, or perhaps 

 Favosites.' 



1 A quartz-pebble containing a crystal of tourmaline is recorded by Mr. S. G. 

 Perceval as found at Sandford-on-Thames, near Oxford (I presume in Drift), 

 Geol. Mag. 1870, p. 96. 



2 I have picked up one or two showing a cone-structure like that easily 

 produced in flint by a blow. 3 Geol. Mag. 1880, p. 405, 



4 Quart. Journ. Geol. Soc. vol. xlv (1889) p. 1. 



