446 
NATURE 
[ Sept. 9, 1886 
another important, if not the principal, source of supply must be 
sought on the north-west. The materials of the basement con- 
glomerates and grits in North Wales appear to be either Palzozoic 
rock or vein-quartz and an impure jasper ; but a microscopic 
study of carefully selected specimens, especially from Anglesey, 
might produce interesting results. In Central England, as the 
Old Red Sandstone is commonly absent, and, if present, must 
have been speedily buried, we should naturally look further afield 
for the materials of the Coal-Measure sandstones and Millstone 
grit, where it occurs. But probably we shall be right in including 
this, as indicated by Prof. Hull, with the northern district. He 
also points out that in the south-western part of England and in 
South Wales there is good evidence that the materials have been 
brought by currents from the west. I have only examined one 
specimen from this region, but it has proved very interesting. 
It is from a Carboniferous grit near Clevedon, in Somersetshire. 
About one-third of the rock consists of quartz grains which I 
should suppose derived from schists or gneisses of moderate 
coarseness ; quite another third of fragments of a very fine- 
grained micaceous schist, about ‘03” long. It is possible that 
these may be phyllites, but I think it far more probable that 
they are true schists. They are very like some of the more 
minutely crystalline schists of Anglesey, and it is evident 
in some cases that the rock had been corrugated subsequent to 
foliation. ‘This grit also contains a few bits of feldspar and flakes 
of mica. I must not forget to mention some curious boulders 
which have been discovered occasionally in actual coal-seams. 
Through the kindness of Mr. Radcliffe I have been able to 
examine some specimens found at Dukinfield Colliery. They 
are hard quartzose grits and quartzites, bearing a general resem- 
blance to sundry of the earlier Paleozoic rocks. One of the 
latter is as compact and clean-looking as the well-known quartzite 
of the North-Western Highlands. Besides quartz, and perhaps 
a little feldspar, it contains a small quantity of iron-oxide (?), two 
or three flakes of white mica, a grain or two of tourmaline, and 
of a mineral resembling an impure epidote. A similar quartzite 
has been found by Mr. W. S. Gresley in a coal-seam in Leicester 
shire, and I have described another from the ‘‘ thirteenth coal” 
at the Cannock Chase Colliery. In each of these quartzites the 
two minerals last named may also be detected. 
Before quitting the Carboniferous series I must call attention 
to some interesting grits which during the last few years have 
been struck in deep borings. In the London district a red 
sandstone, in some places conglomeratic, has been found under- 
lying sundry members of the Mesozoic series. Some have 
thought this of Triassic age, but inasmuch as it is very doubtful, 
as we shall presently see, whether the coarser beds of the Triassic 
formations extended so far to -the east, and the dip of the red 
beds in the well at Richmond agrees better with that of the 
Paleozoic rocks in other parts of the buried ridge, I think these 
sandstones more probably older than any part of the Mesozoic 
series, perhaps not very far away from the base of the Carboni- 
ferous. Inthe boring at Gayton, in Northamptonshire, Lower Car- 
boniferous rocks were succeeded by reddish grits and sandstones. 
The finer beds much resembled the ordinary Old Red Sandstone, 
and, like it, suggested a derivation from fairly coarse-grained 
crystalline rocks. But of the origin of one rock, a quartz-feldspar 
grit, there can be little doubt. I may briefly describe it as very 
like the Torridon sandstone of Scotland, except that the cement 
is calcareous. I do not, indeed, claim for it a like antiquity, for 
I think it far more probably about the age of the lowest part of 
the Carboniferous series ; but it, too, must have been derived 
from granitoid rocks. While some of the grains are fairly well 
rounded, others, especially of feldspar, as in the Millstone 
grit of South Yorkshire, do not seem to have travelled 
very far. 
fermian.—The sandstones of the northern area belonging to 
this formation do not, as far as I have been able to ascertain, 
afford us much information. Quartz grains, of course, abound, 
but as they are rather small, it is not possible to be sure whether 
they have been primarily derived from a granitoid rock or a 
schist. The former, however, appears to me the more probable 
source. ‘They also contain fragments of feldspar still recognisable, 
flakes of mica, and possibly a little schorl. The frequent occur- 
rence of crystalline quartz as a secondary formation in these 
sandstones is a point of much interest, but has no relation to my 
present inquiry. The breccias near Appleby, Kirkby Stephen, 
&c., which I have not seen, indicate that at this time not distant 
masses of Carboniferous limestone, and of earlier Palzeozoic 
rocks, were undergoing denudation; but it appears to me im- 
probable that the finer materials of the sandstones were furnished 
by any rocks in the vicinity. 
The Permians of the central area offer a rich field for future 
work. For the materials of the sandy beds I should conjecture 
a distant source, but for the pebbles in the conglomerates, and 
the fragments in the breccias, we need not travel very far afield. 
The Lower Carboniferous Measures contributed limestone and 
chert, the former being especially abundant in the conglomerates, 
but the ‘‘ vein-quartz, jasper, slates, and hornstone,” mentioned 
by some observers, indicate that yet earlier rocks furnished their 
contingent, while of the igneous materials I will speak directly. 
I shall pass very briefly over the breccias, so well displayed, for 
instance, on the Clent and Lickey hills, at no great distance 
from this town, because I trust we shall have presented to us, in 
the course of this meeting, a sample of the rich harvest which is 
awaiting explorers. Earlier investigators looked towards Wales 
for the origin of these fragments ; we shall, I believe, learn that 
the majority are more probably derived from rocks, which, though 
now almost hidden from view, exist atno great distance. Some of 
the more compact traps may have come from the old rhyolites, 
which, by the labours of your geologists, have been detected 27 sttu 
beneath the Lickey quartzite, while we may venture to refer the 
‘red syenite” and ‘‘red granite” to outcrops of crystalline 
rocks of Malvernian age. These breccias have been regarded as 
proving the existence of glaciers in the Lower Permian age. It 
is, of course, possible that floating ice has been among the agents 
of transport, but after carefully examining the specimens in the 
museum of the Geological Survey on which glacial striz are 
asserted to occur, I am of opinion that the marks are due to 
subsequent earth-movements. On only one specimen did I 
recognise glacial striation, and this pebble is so different from 
the rest that I think it must have come from drift, and not from 
the Permian beds. 
No less interesting are the Permian breccias of Leicestershire. 
These have attracted the attention of an indefatigable local 
geologist, Mr. W. S. Gresley, and to his kindness I am indebted 
for the opportunity of examining both rock specimens and slices. 
As might be expected, fragments, which I have no hesitation in 
referring to the Charnwood series, are not wanting, though 
hitherto they have not occurred in any abundance; but perhaps 
the most interesting member is a tolerably hard conglomerate, 
containing rather abundantly pebbles of a speckled grit and ofa 
compact ‘‘ trap.” Microscopic examination of this conglomerate, 
which varies from a fairly coarse puddingstone to a grit, shows 
that the above-named speckled grit is composed of small and 
rather angular fragments of quartz, associated with grains of 
brownish and greenish material, which may be in some cases 
decomposed bits of a rather basic lava, in others possibly a 
glauconite of uncertain origin. But the ‘‘trap ” pebbles are yet 
more interesting. These are the more numerous, and are com- 
monly well rolled. They probably belong, roughly speaking, 
to one species, but exhibit many varieties. In a single slide I 
have seen at least six, perfectly distinct. Some are indubitably 
scoriaceous, others full of microliths of a plagioclastic feldspar, 
others almost black with opacite, others mottled brown devitri- 
fied glasses, more or less fluidal in structure. Probably they 
belong to the andesite group, with a silica percentage not very 
far away from sixty. In none have I observed any signs of 
crushing or cleavage, so that I cannot refer them to the Charn- 
wood series, but conjecture that they are relics of volcanoes 
later in age than the great earth movements which affected that 
series, though I cannot connect them with the more basic post- 
Carboniferous outbreaks of which we have indications at Whit- 
wick and elsewhere. Quartz grains also occur, and some of 
these exhibit a rather peculiar *‘ network ” of cracks which is 
characteristic of this mineral in the rocks of Peldar Tor, Sharpley, 
&c., and one such grain is attached to a fragment of minutely 
devitrified rock. Hence, as shown by larger fragments, the 
Charnwood series has contributed to the materials of this con- 
glomerate, but the more abundant appear to have been derived 
from volcanic vents, the locality of which is at present 
undiscovered. ? 
Trias.—Vhe Bunter beds and the lower part of the Keuper 
consist of more or les; coarse materials, while in the remainder 
of the latter such deposits are rare and local. Hence it is evi- 
dent that after the deposition of the Keuper sandstones a very 
different set of physical conditions prevail. The lower series 
consists of sandstones and conglomerates ; these beds occur in 
1 I pass by the interesting pebbles of hematite, which have received special 
attention from Mr, Gresley. 
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