258 
trict at such very different levels and in such positions as to pre- 
clude the possibility of their being due to icebergs. Nor could 
the boulders represent the remainder of a mass of drift which had 
been removed by denudation, for the following reasons: (1) 
they were all composed of one rock, and that invariably a rock 
to be found in place close by ; (2) any denudation which could 
have removed the clay and smaller stones of the drift would 
have obliterated the traces of glaciation on the surface of the 
rock ; (3) the boulder which had protected the fine glacial 
markings below it from the action of the rains would certainly in 
some cases have preserved a portion of the stiff boulder-clay ; 
(4) the margin of the boulder-clay along the flanks of Ingle- 
borough was generally marked by lines of swallow-holes, into 
which the water ran off the voulder-clay ; and when the im 
pervious beds overlying the limestone had been cut back by 
denudation, a number of lines of swallow-holes marked the suc 
cessive stages in the process; but there was not such evidence 
of the former extension of the drift up to the Norber boulders ; 
(5) the boulders themselves were not rounded and vlaciated in 
the same way as the masses of the same rock in the drift, but 
resembled the pieces now seen broken out by weathering along 
the outcrop of the rock close by. Having thus shown the im- 
probability of these boulders having been let down out of a mass 
of drift the finer part of which had been removed by denuda- 
tion, or of their having been masses floated to their present posi- 
tion on shore-ice, he offered an explanation of their peculiar 
position, which he thought was not inconsistent with the view 
that they belong to some part of the age of land-ice. That they 
were to be referred to some exceptional local circumstances 
seemed clear from the rarity of such glaciated pedestals, while 
boulders and other traces of glaciation were universal over that 
part of the country. He therefore pointed out, in explanation, 
that they occurred always where there was a great obstacle in 
the path of the ice: at Cunswick the mass of Kendal Fell 
curving round at the south and across the path of the ice; at 
Farleton the great limestone escarpment rising abruptly from 
Crooklands ; at Norber the constriction of the Crummaclk 
valley near Wharfe, and the great mass of Austwich grit 
running obliquely across its mouth. 
had to force its way up hill; and there would be a time when it 
would just surmount the obstacle after a season of greater snow- 
fall, and fall back after warm setsons, until it fell back alto- 
gether from that part. During the season of recession, boulders 
would be detached below the ice-foot ; during the seasons of 
advance they would be pushed forward; and in those excep- 
tional localities of isolated hills from which the drainage from 
higher ground was cut off, the boulders were left on a clean fur- 
rowed surface of limestone, which was then acted upon by rain- 
water and the vegetation, except where protected by the 
boulders. The author said that the reason why he objected 
to any numerical estimate of the time which had elapsed 
since the boulders were left on the glaciated surface was that we 
did know that the rate of weathering in the limestone was most 
unequal. He gave cases from Devonshire and the Lake 
District of extensive weathering in a few years. He had 
called attention to the great acceleration of decomposition 
where the vegetation encroached on the limestone, and he 
maintained that we had 
On some derived fragments in the Longmynd and newer 
Archean rocks of Shropshire, by Dr. Charles Callaway, 
F.G.S, Further evidence was added to that given in the 
author’s previous paper (Q.%.G.S., 1879, p. 661) to show 
that the Longmynd rocks of Shropshire were chiefly composed 
of materials derived from the Uriconian series, and that the 
Uriconian series itself (Newer Archzean) was partly formed from 
the waste of pre-existing rocks. This evidence consisted of (1) 
the presence, throughout the greatly developed Longmynd con- 
glomerates and grits, of purple rhyolite fragments, recognised 
by microscopical characters as identical with the Uriconian 
rhyolites of the Wrekin, and the occurrence of grains, probably 
derived from the same rhyolites, in the typical green slates of 
the Longmynd; and (2) the existence of conglomerate beds 
containing rounded fragments of granitoid rock in the core of 
the Wrekin itself, whilst the Uriconian beds of other localities, 
and especially those of Charlton Hill, contained water- 
worn pebbles, chiefly metamorphic. 
to have been derived from metamorphic rocks of three dis- 
tinct types. The views put forward were founded on micro- 
scopical evidence, of which some details were given in the 
paper, and were supported by the views of Prof. Bonney, who 
In all these cases the ice | 
no constant measure to apply.— | 
NA TURE. 
| spector H.M. Mines. 
These pebbles appeared | 
| to the ice being driven by the wind.—On the Decapod Crus 
[_yuly 15, 1886 
had furnished notes on the microscopical characters of the rocks. — 
Notes on the relations of the Lincolnshire carstone, by Mr. A. 
Strahan, M.A., F.G.S. The Lincolnshire carstone has hitherto 
been supposed to be correlative with the upper part of the Spee-_ 
ton series, and to be quite unconformably overlain by the red — 
chalk (Quart. Fourn, Geol. Svc., vol. xxvi. pp. 326-47). But 
the overlap of the carstone by the red chalk, which seemed to 
favour this view, is due to the northerly attenuation, which is 
shared by nearly all the Secondary rocks of Lincolnshire. 
Moreover, the carstone rests on different members of the Tealby 
group, and presents a strong contrast to them in lithological 
character, and in being, except for the derived fauna, entirely 
unfossiliferous. It is composed of such materials as would result 
from the ‘“‘washing” of the Tealby beds. In general it is a 
reddish-brown grit, made up of small quartz-grains, flakes and 
spherical grains of iron-oxide, with rolled phosphatic nodules. 
‘Vowards the south, where it is thick, the nodules are small and 
sporadic. Northwards, as the car-tone loses in thickness, they 
increase in size and abundance, so as to form a ‘‘ coprolite-bed,” 
and have yielded specimens of Ammonites speetonensis, A. plic-— 
omphalus, Lucina, &c. When the carstone finally thins out, — 
the conglomeratic character invades the red chalk, similar 
nodules being then found in this rock. ‘The presence of these — 
nodules, with Nescomian species, taken in connection with the 
character of the materials of the carstone, points to considerable 
erosion of the Tealby beds. On the other hand, there is a pas- 
sage from the carstone up into the red chalk. It would seem, 
then, that the carstone should be regarded as a “‘ basement-bed” 
of the Upper Cretaceous rocks. ‘The Lincolnshire carstone is 
probably equivalent to the whole of the Hunstanton Neocomian, © 
the impersistent clay of the latter being a very improbable re- 
presentative of the Tealby clay. It therefore follows that the 
whole Speeton series is absent in Norfolk, and also in Bedford- 
shire. ‘The unconformity at the base of the carstone becomes. 
greater southwards, and the nodules have been derived from 
older rocks. Similarly north of Lincolnshire, where the Speeton — 
series is overlapped, the nodules in the red chalk, marking a” 
horizon of the carstone, have been derived from oolitic rocks. 
In the south of England it would se*m that equivalents of the 
Speeton series reappear. The Atherfield clay contains an in- 
digenous Upper Speeton fauna, while a pebble-bed near the — 
base of the Folkestone beds is described by Mr. Meyer as con 
taining derived oolitic pebbles, and being probably the repre- — 
sentative of the Upware deposit, and presumably, therefore, 
also of the Lincolnshire carstone.—The geology of Cape Breton” 
Island, Nova Scotia, by Edwin Gilpin, Jun., F.R.S.C., ie 
After referring to previously published 
descriptions of Cape Breton geology, the author stated that th 
various formations found in the island had been thus classified 
by the officers of the Geological Survey :— 
Pre-Cambrian (Laurentian) 
including 
‘d 
| 
The Felsite series. 
The Crystalline Limestone series. 
Lower Silurian. 
Devonian. 
Carboniferous, including 
- Lower Coal-formation. 
| { Gypsiferous series. 
| Limestones, &c. 
| © Millstone- Grit. 
\ Middle Coal-formation. 
He then proceeded to give an account of each system and its 
subdivisions in order, commencing with the most ancient, and 
adding a few detailed sections of the rocks belonging to some of 
the principal series. He described the distribution and relations 
of the several divisions. The paper concluded with a few not 
on the superficial geology of the island. There is a gene 
absence of moraines and of the fossiliferous Post- Pliocene marine 
clays of the Lower St. Lawrence. The older beds are generall) 
exposed, but deeper soils and deposits with erratic boulders 
found overlying the Carboniferous beds. Marks of recent ic 
action are found on the shores of some of the lakes, and are due | 
ceans of the Oxford Clay, by James Carter, F.G.S. The auth 
commented on the paucity of these fossils as indicated in Britis] 
lists, only three or four species having hitherto been recorded. 
