138 Reports and Proceedings—Geological Society of London. 
overlying rocks are described by Prof. Bonney, and he recognizes 
amongst them three well-marked types. In No. 1 he includes the 
Torridon sandstone, the quartzites and the supposed overlying flagey 
beds on the east side of Glen Laggan. ‘These are partially metamor- 
phosed, only distinct fragments are always easily recognizable in them 
in abundance. In No. 2, the Ben-Fyn type, the rocks are crystalline 
throughout, being typical gneisses and mica-schists. In No. 8, the Lock- 
Shiel series, he recognizes highly typical granitic gneisses of the Lower 
Hebridean type. Dr. Hicks failed to find in these areas at any point 
the actual passage from group 1 to group 2; neither did the same 
rocks belonging to group 1 meet usually the same rocks belonging 
to group 2. The evidence everywhere showed clearly that the con- 
tacts between these two groups were either produced by faults 
or by overlapping. Group 3, placed by Murchison as the highest 
beds in a synclinal trough, supported by the fossiliferous rocks, 
the author regarded as composed of the oldest rocks in a broken 
anticlinal. They are the most highly crystalline rocks in these areas ; 
and the beds of group 2 are thrown off on either side in broken 
folds. These, again, support the rocks belonging te group 1. The 
author therefore feels perfectly satisfied that the crystalline schists 
belonging to groups 2 and 8, which compose the mountains in the 
central areas, do not repose conformably upon the Lower Silurian rocks 
of the north-west areas with fossils, and that these highly crystalline 
rocks cannot therefore be the metamorphosed equivalents of the 
comparatively unaltered, yet highly disturbed and crumpled, richly 
fossiliferous Silurian strata of the southern Highlands, but are, like 
other truly crystalline schists examined by him in the British Isles, 
evidently of Pre-Cambrian age. 
In an Appendix by Prof. T. G. Bonney, F.R.S., Sec.G.S., on the 
Lithological Characters of a Series of Scotch Rocks collected by Dr. 
Hicks, the author stated that he observed in the above series, as he 
had done in other Scotch rocks lately examined by him, three rather 
well-marked types :—one, where, though there is a certain amount of 
metamorphism among the finer constituents forming the matrix, all the 
larger grains, quartz, felspar, and perhaps mica, are of clastic origin ; 
a second, while preserving a bedded structure and never likely to be 
mistaken for an igneous rock, being indubitably of clastic origin, retains 
no certain trace of original fragments; while the third, the typical 
‘old gneiss’’ of the Hebridean region, seldom exhibits well-marked 
foliation. It is sometimes difficult to distinguish between the first and 
second of these; but this the author believed to be generally due to 
the extraordinary amount of pressure which some of these Scotch rocks 
have undergone, which makes it very hard to determine precisely what 
structures are original. Even the coarse gneiss is sometimes locally 
crushed into a schistose rock of comparatively modern aspect. The 
least altered of the above series the author considered to be the true 
‘‘newer-gneiss’’ series of the Highlands, but both of the others to be 
much older than the Torridon Sandstone. 
2. ‘On the Lower Carboniferous Rocks in the Forest of Dean, as 
represented in typical sections at Drybrook.”” By E. Wethered, Esq., 
F.G.S., F.C.S. With an Appendix by Dr. Thos. Wright, F.R.S., F.G.8. 
