138 PROF. BONNEY ON THE RELATION OF BRECCIAS [May 1902, 
but those of smaller size are numerous. At Northfield, however, 
many measure about 9 inches, not a few about 12 inches, and one was 
21 inches across. Now and then in the Clent district pieces quite 
2 feet broad have been found :’ these are usually Llandovery Sand- 
stone. In some localities fragments of a compact igneous rock are 
so abundant, that the deposit obtained the name of ‘trappoid’ or 
‘trappean breccia.’ 
According to Mr. Wickham King, who has studied the materials 
of the Midland Permian more minutely than any predecessor, 
Carboniferous Limestone usually predominates in the underlying 
conglomerates, while the breccias in most places are formed 
of yet older rocks, namely, of compact felstones (late pre-Cambrian 
volcanics), tuffs and agglomerates, hilleflintas, Cambrian quartzite, 
and Silurian rock, especially Llandovery Sandstone: the majority 
of these representing older Palzeozoic or late pre-Cambrian rocks, 
which are exposed to view (being brought up by faults) on the 
western flank of the Clent range. 
Two explanations have been offered of the origin and mode of 
transport of the materials of these breccias. Sir Andrew Ramsay, 
followed by Prof. Hull, thought that they had been carried by floating 
ice from the Welsh Borderland, 20 or 30 miles away, and asserted 
that some of the fragments bore glacial striations. But the 
specimens exhibited at Jermyn Street always appeared to me to 
have been marked by mutual pressure, and this view, I am glad to 
find, commends itself to Mr. Wickham King. He also points out 
that the thickness of the breccias in the Clent and Enville districts 
is greatest at their southern extremities,” and that they have been 
derived from rocks im situ to the south or south-east in the 
‘Mercian Highlands, of which a little is exposed in the above- 
named tract, but the major part is concealed beneath the Trias. 
The Permian deposits of Leicestershire have been admirably 
described by Dr. Horace Brown,? and I obtained some further par- 
ticulars as to the materials of the breccia from the study of a collection 
made by Mr. W.S8. Gresley.4 Here outcrops are few, the whole 
system is thin,’ and the breccia at most a few feet thick. The 
fragments, according to Dr. Brown, are embedded in a calcareous 
sandy matrix, are generally angular, and seem to become more so in a 
southerly direction. They are derived from rocks of various ages, 
the proportion varying with the locality. The Carboniferous 
Shales are generally well represented, amounting occasionally to 
1 As stated by Mr. Wickham King (op. cit.) and more fully explained in a 
written communication (to which I am much indebted), the size of the fragments 
varies much in different localities. 
= The thick breccia at Clent is replaced by sandstone at Sedgeley (8 miles) ; 
that at Northfield has nearly died out at Handsworth (5 to 6 miles); and two of 
the Enville breccias almost or quite die out in 4 miles. 
3 Quart. Journ. Geol. Soc. vol. xlv (1889) p. 1. They were also briefly 
described by Prof. Hull, Mem. Geol. Surv. 1860 ‘ Leicestershire Coal-Field.’ 
4 «Midland Naturalist’ vol. xv (1892) pp. 25, 49. 
° Only in one case does it exceed 30 feet. The breccia seems to vary in 
position ; o¢casionally there are two seams, and the total thickness is something 
like 4 yards. 
