February 11, 1916.

THE COLLIERY GUARDIAN.

263

tanks, was 24,-200 lb. in 65 minutes — 23,408 lb. per hour,
giving a steam consumption of 34-76 lb. per kw. hour.
The barometer stood at 30-25 in., and the vacuum 28-75.

Tests with High-Pressure Steam.—During this test it
was impossible to obtain the full power of the turbine,
and the average power generated was 1,032 kw., with cos
<f> =0-823. The load was chiefly applied by means of
water resistance, but some current was taken for the
use of the pits.

From fig. 4 it will be seen that the guaranteed steam
consumption C D with high-pressure steam, at the
power generated, was 22,0001b. per hour, which equals
21-34 lb. per kw. hour, writh a vacuum equal to 93-4 per
cent, of the theoretical, and a steam pressure of 113 lb.
per sq. in. absolute.

The amount of condensed steam measured in 3,735
seconds was 19,8001b., or 19,1401b. per hour, giving an
actual steam consumption, under working conditions,
of 18-54 lb. per kw. hour. The steam pressure in front
of the steam valve was 114-1 lb. per sq. in.; the tempera-
ture 337 degs. Fahr. In front of the first stator the
pressure was 79-5 lb., and the temperature 320 degs-.
Fahr. The temperature in the exhaust chamber was
85 degs. Fahr., the vacuum 29-1 in., with a barometer
of 30-1 in. The speed of the turbine was the same in
this test as the previous case, viz., 3,050 revolutions per
minute.

The tests have shown that the steam consumption on
both tests are lower than the guarantee, and that the
estimated advantages have been realised. The plant
fulfils all expectations. The great saving effected by
utilising the exhaust steam in this manner is shown by
the fact that before the alteration electrical energy to
the value of £150 to £200 per month had to be purchased
for other pits, whilst since the introduction of the tur-
bine, not only is the above sum saved, but also current
to the value of £150 per month is sold, although there
has been no increase in steam consumption.

LECTURE OH “COAL.”

The fourth lecture on “ Coal ” was delivered at University
College on the 8th inst. by Dr. Marie Stopes. The lecturer
considered the special light thrown on the composition of
coal by the stone masses found in the heart of some coals,
and known to the miners as “coal balls.’’ Detailed proof
from their shape, structure, chemical composition, position
in the seam, etc., was advanced, to show that the mass of
debris enclosed and petrified in the coal balls actually
represents the vegetable mass from which the surrounding
coal was formed. For example, specimens of adjacent coal
balls, lying in situ with a streak of coal between them, .in
several cases show portions of the same stem in the two
balls, the parts of the stem in the balls being petrified,
uncrushed, and the parts of the stem outside being crushed
and forming ordinary coal. Such specimens and their
importance were first described by Stopes and Watson, and
show that the coal balls could not have been shifted since
their formation when the coal-forming mass was still com-
paratively uncrushed and undecayed.

The chemical analyses of the balls show that they are
primarily dolomitic, with very varying proportions of
CaC03 and MgCO3; these two minerals, however, being
generally about 90 per cent, or more of the whole mass.
The probable process of their formation from sea water,
which had filtered into the still soft coal forming mass, was
described; the GaS04 and MgS04 present in sea water being
reduced by the carbon set free from the small portion of the
decaying vegetable debris

Microscopic sections through the coal balls showed the
humic nature of the mass, which consists of quantities of
uncrushed leaves, twigs, roots, seeds, and spores, the latter
in comparatively small numbers when compared with aver-
age sections through the coal itself. Surrounding these
larger fragments is a fine mulch of extremely minute and
decomposing debris which has the appearance of having
formed a soft and jelly-like mass, .and which .also probably
was the source of the carbon, which effected the reduction of
the sulphates.

It is particularly noticeable that the fragments found in
such excellent preservation in the coal balls are by no means
the old, faded, or decaying debris, which is so often described
as forming the coal, but are frequently young actively-grow-
ing portions of plants, the active tissue of which may be in
the very midst of growth, and even of cell division.

Comparing the material in the coal balls with that found
in the coal itself, it becomes evident that much of the decom-
position took place after the debris had already been collected
in the coal-forming layer, and that during the coalification
of this humic, mixed debris spores became proportionally
more important, solely owing to their greater resistance to
decay. The recent distinction made by chemists between
“ humic ” and “ resinous ’’ material in the coal was con-
sidered as arbitrary, since all the material forming the coal
being essentially humic (fragments of plants), whilst only
the fragments of a particularly resinous and waxy nature,
like spores and resin exudations, had a persistence which
carried them comparatively unchanged through conditions
which more profoundly altered the originally more numerous
foliage and other fragments.

The huge mass of coal balls completely replacing the seam
at Shore was described, and its evidence that, even after sub-
mergence under the sea, the seam was originally more than
double its present thickness, was noted. The next lecture, to
which those interested in mining, etc., are admitted free, will
be held at 5 p.m. on Tuesday, February 15.

Grimsby Coal Exports. — Beturns for the week ending
February 4 show that the coal exported from Grimsby was
as follows :—Foreign : To Dieppe, 2,415 tons ; Esbjerg, 2,054 ;
Odense, 727; Rotterdam, 524; and Treport, 2,505 tons. Coast-
wise : To Dagenham, 2,600 tons; Great Yarmouth, 560 tons
—total, 8,225 tons foreign, and 3,160 tons coastwise; against
4,074 tons foreign during the corresponding week last. year.

Mining Institute of Scotland.—A general meeting of the
above institute will be held in the Heriot-Watt College,
Chambers-street, Edinburgh, on Saturday, 12th inst., at
3 p.m. Mr. Sam Mavor’s paper on “ Compressed Air for
Coal Cutters ” will be discussed, as will also Mr. James
Black’s paper on “ Forming a Shaft Pillar in Thin Seams.’’
Mr. Henry Briggs will read a paper on “ A Device for the
Bapid Estimation of Oxygen and Blackdamp in Mines.”

The Connection Between the North-western European Coal Fields.*

By Prof. X. STAINIER, D.Sc.

Introduction.—The connection between the Kent and
the Continental coal fields on the one hand, and the
Western British coal fields on the other, has been for
many years a controversial subject between geologists.
These coal fields were once considered as detached por-
tions of a former extensive sheet of carboniferous
deposits, but some geologists seem now inclined to the
view that the fields were never connected. The author
hopes to show that both of the extreme theories must
be set aside. The re-survey of the British coal fields has
provided accurate stratigraphical knowledge and maps.
In the North of France, in Belgium, Holland, and in
the Rhenish provinces much work has also been per-
formed in the same direction.

PHYSIOGRAPHY OF N.W. EUROPE DURING THE
CARBuNIFEROUS PERIOD.

The post-carboniferous mountain ranges are especially
connected with the problem of denudation and the sever-
ance of the various coal fields. The pre- and inter-
carboniferous seismic movements are connected with
other questions.

Two mountain ranges only are of interest in relation
to the coal field problem—the Caledonian Range (Ed.
Suess) and the Hercynian Range (Marcel Bertrand).
Before and after the carboniferous period these ranges
covered North-West Europe with such a network of
ridges and troughs that some classification is needed (as
that given below), with suitable terminology to avoid
misunderstanding :—

Mountain p	t n	Direction

I old.	Trend. of	Names.

ian8e>	impulse.

Caledonian..Longi-... N.E. to S.W. ...N.W.... Caledonian

tudinal	N.N.E.toS.S.W.	S.E.	
Trans-... versal	N.W. to S.E. ..		.. Charnian
Hercynian ...Longi- tudinal	E.toW.  E.N.E.to W.S.W.  W.N.W.toE.S.E.	.. S.	... Hercynian
Trans-...	N. to S.	. E. .	.. Malvernian

versal

After discussing these folds in detail, the author deals
with the physiographical conditions of the lower carboni-
ferous period.

Physiography of the Upper Carboniferous Period.

The main Caledonian ridge was still existing as the
south-east shore of a. continent. Southwards an
unbroken but shallow sea, with a few islands, stretched
up to the . Cornwall-Hartz1 anticline. In the main
Caledonian syncline in Scotland and. Ireland and in
North-East England, the formation of coal had already
set in. No important phenomena serve to mark the
dawn of the coal measures period except, perhaps, a
general earth’s crust movement, which was no doubt
very regular and slow, and resulted in a gentle folding.
In some places the upheaval was sufficient to produce
local disturbances. The phenomena of coal formation
seemed to come to a standstill, but soon set in again
slowly and locally, until at the beginning of the middle
coal measures it took a sudden and marvellous impetus.
The difference between the physiographical conditions
of the lower and of the upper carboniferous is such as to
raise a difficult problem regarding the causes. There is
an important change in the sediments of both periods,
which the above movement is unable to explain, as the
lower carboniferous sea was nearly always a shallow sea,
but the formation of coal makes a still more important
contrast. Indeed, coal deposits exist throughout the
geological -series of strata. Nevertheless, during the
carboniferous period coal formation took place on a scale
which has never been equalled since, thus pointing out
that the coal measures deposits owe their coal to a
fortuitous gathering of suitable conditions. Among those
conditions the writer may quote :—(1) The neighbour-
hood of mountain ranges condensing heavy rains, and
yielding ample material to erosion and sedimentation.
For this purpose the main Hercynian anticline towards
the south, and the main Caledonian anticline, played an
active part in the phenomena. (2) The enormous thick-
ness of the-coal measures, showing throughout a con-
tinuous repetition of the same lithological character,
clearly indicates that subsidence of the earth’s crust kept
pace with sedimentation.in the coal-forming areas. Such
concordance may have resulted from the slow and
gradual sinking of broad -synclines, and .the correspond-
ing upheaval of intervening anticlines,..both movements
producing a general and gentle folding. That such a
folding took place during the coal measures period in
North-West Europe we have plenty of evidence, this
folding being the result of posthumous Caledonian and
precursory Hercynian movements. (3) Peculiar climatic
conditions, such as temperature, moisture, rain, and
light, seem no less necessary, but perhaps the most
powerful factor was the chemical composition of the
atmosphere rich in carbonic acid yielded by volcanic
eruptions. As for the difference in the lithological
character of the sediments of both divisions of the car-
boniferous, it is doubtless the result of important changes
in Continental denudation. Limestones are produced
during dry and warm periods, while the transport of
sediment to the sea is unimportant. On the contrary,
sandy and clayey sediments are produced during warm
and wet periods of active Continental erosion and trans-
port. A good deal of the coarse rocks of the coal
measures owe part of their origin to the disintegrations
of granite rocks, for granite pebbles and minerals
(felspar . porphyritic quartz) are common, in . these
rocks. We have every reason to trace these constituents

* Abstract of a paper read before the Manchester Geological
and Mining Society.

to their origin in the archean and eruptive rocks of the
northern and southern boundary of the great carboni-
ferous belt.

The Lower Coal Measures Period.—The work of classi-
fying and zoning the strata of this division is still imper-
fect in many coal fields; the writer is prevented from
dwelling on this subject. From a lithological, as well
as from a geographical, standpoint, this division is much
more connected to the foregoing one than to the coal
measures, thus showing that no great change intervenes
between them.

The Middle Coal Measures Period.—This is really the
period of coal formation during which all the favourable
conditions prevailed. Important geographical changes
took place, and the leading features of the future her-
cynian folds began to get shape; and the writer will
point out some of them.

Westmoreland Anticline.—From the existence of the
Ingleton coal field, in the very middle of this anticline,
one might suppose that middle coal measures formerly
extended all over it. But from recent researches, this
does not seem to have been the case. From the study
of borings put down in this coal field, W. Gibson believes
that the red sandstone measures capping this coal field
are conformable with the middle coal measures below,
since there is a gradual transition from one to another.
In these middle coal measures, N. Arber detected /
Dictyopteris Sub-Brongriatiti, a plant which charac-
terises the top of the middle coal measures. Then, these
red measures might belong to the transition coal
measures, and the lower coal measures and lower middle
coal measures should be wanting on the top of the
anticline, pointing out that during the formation of these
divisions the anticline had emerged. Should further
researches give ground to this supposition, the history
of the Ingleton coal field should have been nearly the
same as the history of some Midland coal fields (South
Staffordshire).

Midlands Syncline. — Meantime, this syncline was
slowly going on, with the subsidence already observed
during the foregoing periods, and through the subsidence
the overlapping of the Mercian highlands made further
progress. C. Lapworth has shown how, on the south
margin of the Midland coal field, each division was, in
turn, overlapped by the following one, until at last the
upper measures came to rest near or over the top of
these highlands, hiding their rugged floor under a blanket
of coal measures rocks. ■. By the uneven surface upon
which they were deposited we can understand the irregu-
larities of shape and thickness of the South Midland coal
field, the varying thickness of the coal seams, the pro-
truding bosses of older rocks, and the various ages of
their strata. Jukes long ago pointed out how the
peculiar characters of the most typical of these coal fields
—those of South Staffordshire—are in accordance with
their peculiar geographical conditions. It was only a
little while before the end' of the period that the most
southern coal fields were covered by middle coal
measures, and it is quite probable that, at least along
the Welsh borderland, the middle coal measures never
crossed the Wales anticline, for along the Malvernian
axis there is a row of inliers of upper or transition
measures resting on older rocks, without any inter-
positions of middle measures. The middle measures of
the Titterstone Glee Hills no doubt by their characters
belong to .the Midland type. Therefore the Shropshire
plateau, whose slope was dipping southwards during the
Tournaisian, became inclined northwards since the
Visean period.

Among the many questions relating to the geological
history of the Midland coal fields, the writer will deal
with the relationship existing between' the various por-
tions of the main coal field. On first consideration, so
much irregularity seems to prevail among the southern
midland coal fields, with respect to their distribution,
shape, outlines, and thickness, that one might believe
they were always independent, inasmuch as different
types of rocks are to be found in these basins. Opti-
mistic views with regard to their underground connec-
tions have sometimes been upset by recent researches.
Nevertheless, they possess such ‘a similarity of impor-
tant characters that there is ground _to?believe in their
original connection. In this respect, ‘the writer may.
quote : (1) Nearly all these coal'fields present the same
marine beds with the same fauna. ’ According to the life
conditions of marine beings, they cannot migrate from
basin to basin except by sea water communications.
This is especially so for open sea animals, such as
cephalopoda and encrinites, the former being conspicu-
ously abundant in these .marine beds. Marine fauna
have been detected in the middle measures of the coal
fields of Leicestershire, Warwickshire, South Stafford-
shire, and Coalbrookdale, and they are still more plen-
tiful in all the coal fields around the central Pennine
chain. Marine fauna have not yet been detected in the
Wyre Forest, due no doubt to lack of researches. (2)
Mussel banks or beds crowded with shells of the family
of Carbonicolidce are plentiful in many of these coal
fields. Although the evidence afforded by the presence
of such fresh water or brackish shells is, by far, less
important, nevertheless, we may imagine that such
shells living in quiet waters and in mud had no means
to cross land, especially when no flying vertebrates
existed to carry their germ. (3) As for the difference
between the sediments of some coal fields, they are not
of such a kind as to render a common origin inadmis-
sible. Geologists who have had the opportunity of
mapping coal fields are acquainted with the difference
they always display owing to sundry local conditions,
but, by a minute survey, it is often possible to trace the
gradual passage from one sediment to the other. (4)
The more or less detached condition presented, nowa-