June 2, 1916.

THE COLLIERY GUARDIAN

1041

MIDLAND INSTITUTE OF MINING, CIVIL
AND MECHANICAL ENGINEERS.

Earth Movements in South Yorkshire.

The question of the effects of earth movement on the
coal measures of South Yorkshire and the neighbouring
parte of West Yorkshire, Derbyshire, and Nottingham-
shire, which was brought before the annual meeting of
the Institution of Mining Engineers in September last by
Prof. W. G. Fearnsides, of the University of
Sheffield, was further discussed by him before the Mid-
land Institute of Alining, Civil, and Mechanical
Engineers on Saturday, May 27, when he presented the
second part of his paper (sec p. 1039 of this issue). The
meeting was held at the Danum Hotel, Doncaster, the
President (Mr. C. C. Ellison) in the chair. There was
a good attendance.

The following elections took place :—Member, Mr.
Owen Walters, Dundee Coal Company Limited, Club
Arcade, Durban, Natal, South Africa, proposed by Air.
Percy ' N. Hambly, seconded by Air. Frederick
Chambers; associate member, Air. Christopher Barber,
60, Harcourt-road, Sheffield, proposed by Air. A.
Victor Derry, seconded by Mr. G. Stanley Cooper.

Discussion.

The President, in opening the discussion, said they
were all most indebted to Prof. Fearnsides for his very
valuable paper, and for the great amount of trouble
which he must have taken in preparing it. Prof. Fearn-
sides had told him that, besides being very busy, he had
had other things which had impeded him in completing
the paper as he would have liked. Evidently somebody
knew how valuable his writings were, for he had had a
visit from burglars, who, besides stealing his papers,
took some of his spoons and forks. He had had to
re-write a portion of his paper in order to complete it in
time for that meeting. The information which Prof.
Fearnsides had brought before them required careful,
study. _He proposed a very hearty vote of thanks to the
author for the trouble he had taken in preparing the
paper. The resolution was carried.

Air. A. Lupton referred to the paper as most interest-
ing and instructive. It was a great treat to him to listen
to a paper by a geologist, because those gentlemen who
had given their minds to the scientific study of geology
had acquired the logical habit. They went by mathe-
matics to a great extent. They first ascertained their
facts, and then drew their conclusions. There was a
great tendency in this world to draw conclusions first,
with absolute certainty, and then to ascertain the facts,
but a scientific geologist did. the reverse. Forty-five
years ago he himself drew a map of the coal field from
Leeds to Nottingham, showing all the outcrops, and all
the information that he could get hold of from geologists
and Government maps. If there had been as many
facts known then as there were now, that map might
have been different in some particulars. The professor
had referred to the depression of the coal field that took
place during the laying down of the successive beds of
rock and coal, so that they got the total thickness of
5,000 ft. of coal measures deposited in succession. Now,
what was the cause of that continual depression? Was
it the weight of the strata deposited which caused this
gradual depression—that the more stuff the rivers
brought down from the mountains and laid out in the
estuaries the greater the- weight, and consequently the
greater the depression, this continuing to increase as
long as there were any mountains to' wear down? If so,
why did it stop? What was the basis upon which the
strata rested? What was the support? What were
they standing on—that was what he would like to know.
People who looked on a little map of the earth’s surface,
of a section Bin. in diameter, thought they might be
standing upon an archway, but when they remembered
that the centre only rose about 2 ft. in an arch that was
a mile long they had something which an ordinary
bridge builder or stone mason wTould consider nothing
. at 'all. So he did not think they were standing on an
archway. It was the business of the scientific men to
tell them what they were standing on. He remembered
one time when Prof. Green was giving evidence in the
House of Parliament, a learned counsel said to him,
“ Well, Prof. Green, do you pretend to be able to see
through rocks, and tell us these things that nobody has
seen? Have you—to quote Sam Weller—‘ a double
million magnifying power gas microscope ’? ” Prof.
Green replied, “ Yes, it is my profession to study these
things, and I am able to tell you things that you cannot
tsee.” On the question of depression, there were gentle-
men present who knew what amount of volcanic agency
had been at work in those regions. He knew that in
some part of the coal field there had been, a great deal of
that agency. AVell, if they had an opening half a mile
in diameter, out of which a tremendous stream of gas,
which came from mineral substances, was perpetually
pouring, and occasionally dust and stones, they could
only imagine that lit left a cavity somewhere. Of that
he was certain, and he would just like to put the
question as to how far these volcanoes had any effect in
withdrawing support from the surface. Referring to the
published first part of Prof. Fearnsides’ paper, he said
that the author gave an account of a wonderful and
interesting discovery by Mr. Clifton Sorby as to the
amount of water which wras mixed up with and remained
in the mud until subjected to an enormous pressure,
which drove the water away. That was put as a weight
of 1,250 tons on the sq. in.; but he thought this must be
a clerical error for 1,250 lb. Shortly afterwards the
professor said that, taking the specific gravity of the
ground at 2’5, this would mean a depth of 2,700 ft. He
(Air. Lupton) accepted the gravity as 2’5, but he thought
it would mean a depth of about 1,350 ft., and that at
that depth they would have a pressure sufficient to drive

out the water. He should like to know how that water
got away. Of course, the expulsion of the water was
not effected in a hurry; it went very gently. But, still,
they knew that the form of a great deal of the coal
measures, as they were to-day, would resist a great
pressure of water without its escaping through at all; so
that he wanted to know whether that water came away
through fault slips, or through cracks in the strata, or
came so slowly that it gradually got through some
microscopic pores in the coal. He was delighted with
the paper, and the useful and valuable information
which Prof. Fearnsides had taken the trouble to get
together for their use.

Prof. Kendall’s Views.

Prof. P. F. Kendall (University of Leeds) said it
was difficult to criticise the paper without having had
time to digest the mass of information which it con-
tained. He congratulated the Institute and Prof.
Fearnsides upon what appeared to be a very admirable
piece of work, conceived with great ingenuity and
carried out with great industry. He felt reluctant to
enter into the details, because he had not had time to
digest them all, and also because he did not want to
make premature or imperfect disclosure of any work
upon which he • was himself engaged. The contour
method was one which had been applied in many areas.
Prof. Lupton many years ago attempted to project a
plane of the base of the permian rocks forward to the
westward up into the air, as Prof. Fearnsides had done
with a considerable amount of success. That, he
thought, was an exercise perhaps less hazardous than
projecting it forward to the east. The amount of infor-
mation we possessed regarding the permian rocks east
of the outcrops was exceedingly small—some dozen or
two of boreholes and shafts—and these displayed dis-
crepancies which he was afraid would scarcely justify
the.,regularity of the lines that had been drawn. Indeed,
where Prof. Fearnsides’ lines extended from the known
region to the unknown, they became more generalised ;
and when people began to generalise, others began to
think that as the information declined the generalisation
enlarged. They had singularly little evidence of the
steady and regular increase of the permian rocks to the
northward. They had two' or three boreholes in the
Selby area, and then a vast hiatus from there to the
mouth of the Tees. He did not think that one would be
justified in projecting contour lines over the great inter-
vening area of perhaps 60 or 70 miles upon such
imperfect information as that. He must feel a certain
degree of personal gratification, to find that rather bold
speculations and generalisations of his own had been
sustained in some measure by Prof. Fearnsides’ work.
There might be some in that room who had seen a copy
of a very small scale map that he ventured to put before
the Royal Commission on Coal Supplies, giving bis
views as to the probable or possible extension of the
concealed coal field. That portion of the map which
wais extended in a south-easterly direction into the Fen
country was rather severely adversely criticised by
members of the Geological Survey at the time. That
extension of the coal field was, he thought, considerably
sustained and justified by the work that Prof. Fearn-
sides had done. Prof. Fearnsides had accepted the
Charnian ridge—a very complex ridge of ancient rocks
extending from Charnwood, with a .general north-west-
south-east direction. He (the speaker) suggested that
that furnished a line which would be approximately
parallel to the boundary of the coal field in that direc-
tion, and Prof. Fearnsides’ work seemed certainly to
justify it to that extent. When one came to consider
the contouring of the Barnsley bed, it was very
ingeniously worked out, and in its main lines he
should be disposed to agree with it, but he had yet to
consider, from the data now put into his hands, whether
the faults could be ignored. He fancied they could not.
Prof. Hull, many years ago, endeavoured to analyse two
sets of movements—one set of north-east-south-west
foldings (the Pendle direction), with another (the
Pennine) intersecting north and south, with a related
fold running east and west. He endeavoured to trace the
order of succession of the movements that produced
these two sets of folds. Now, in considering the course
of the northern limit of the coal field—upon which, it
was evident, Prof. Fearnsides and himself would not
entirely agree—he (Prof. Kendall) looked into this
question rather carefully, and he found that the actual
termination of the Yorkshire coal field on the north was
partly by dip and partly by a great master fault. That
fault obeyed the law—or rather followed an average of
behaviour—which was common to a great many of the
great faults of this coal field, namely, it had an increase
of throw in the easterly direction. The boundary fault,
where it formed a definite boundary of the coal field,
commenced with a small throw on the west, and with a
greatly-increasing throw towards the east. As it was
traced eastwards, its throw was found to increase very
considerably, and this was most significant as bearing
upon the question of dip. If they had a great fracture
in one direction, and then another system of fractures
that tended to intersect it, the earlier fault would end
off the later ones, which would simply run against it and
make no further progress. It was just as if one.were to
scar a window with a crack : any subsequent cracks
would run against the first, and not cross over it. He
found that the north-west—south-east faults did, so far
as information was available, run up against that east
and west fault, whence he concluded that the east and
west faulting was prior to the south-west and north-east
faults. Everyone knew the enormous fractures in the
south-west—(north-east direction. That had a bearing,
too, upon the question of the further extension of the
coal field to the north, and he had that in mind when he
ventured to draw up a small scale map. He did not want
to be taken too literally and exactly. Dr. Walcbt Gibson
had applied a clinometer to an imaginary section crossing
his (the speaker’s) assumed barrier, and had pointed out
that the Selby borehole disclosed a probable thickness of

coal measures that could not be eliminated along his line
unless a rather considerable dip were imported. But
Dr. Gibson in that case had quite omitted to take
account of this great fault. The fault did extend under
the permian rocks, and therefore they might have a very
great depth of coal measures on the south side, and none
at all on the north side, which was actually the case.
He had listened to the paper with very great (interest.
He should study it with careful attention, and he hoped
that it was merely the first of a series of papers of that
type. The method, as he had said, had been employed
previously. Mr. Cosmo Johns employed a somewhat
analogous method—although, being a very busy man, he
was unable to apply it in such detail as Prof. Fearnsides
had done'—to the consideration of contemporary move-
ments during the deposition of the coal. He (the
speaker) had also applied the method, and had solved a
rather knotty problem in regard to' one of their very
important seams in the northern part of the field, and in
due time he would produce his results.

Mr. Lupton said there was one more question he
should like to put. He had asked how it was that the
depression took place, suggesting that it was by Weight.
He should also like to ask how the elevation took place.
—Prof. Joly, of Dublin, said that the elevation took
place in consequence of the radium that was in the soil,
and that the mighty Himalaya had been raised to their
height of 30,000 ft. by that action.

Prof. Fearnsides’ Reply.

Prof. Fearnsides, in reply, said the paper was the
presentation of work which had interested him very much
indeed, and, as it grew, the mere circumstance that he
had had to go to all the places that he wanted to know
about had given him an insight into the coal field that
possibly, if he had not undertaken the work, he would
never have got. He was afraid that the questions raised
by Mr. Lupton were too hard for him, and did not belong
to that part of his education which had not been
neglected. Air. Lupton had mentioned radium as one
explanation, but he was not at all clear that one. could
not argue in the other direction,' that those who
explained things by radium explained everything by
radium, and it did not always follow that they carried
an argument only to its logical conclusion. He was
afraid he did not know anything about it. He would
look very carefully into the question that Air. Lupton
had raised about some arithmetical errors that pro-
bably had crept into the other portion of the paper, and
would submit an answer in writing if he could. As to
the question of support, that 'was one which one could
not go into in discussing a small district. Heim, in
discussing the Alps, had gone into the matter very care-
fully, and one could give the answer that he gave with-
out knowing that it was particularly applicable to this
district. On the whole, he was inclined to say,
“ Please, it iis not my business.” He was very grate-
ful to Prof. Kendall for his kindly remarks concerning
that portion of his work. But he did not agree that he
had accepted the Charnian ridge. The evidence made
it so clear that it was not a question of accepting. One
could not help it. The facts cried out that Prof.
Kendall’s explanation of the Charnian ridge was the
only explanation that could stand. Therefore, it was
not that he had accepted any evidence at all; Prof.
Kendall was certainly right in that matter. With
regard to the northern limit of the coal field, he had
carefully kept 'away from any detailed discussion of the
northern district. He had certainly been up to see some-
thing of the pits in that region, but he had really done
no more than allow straight lines, or contour lines, to
meet, and there he had ended off. He had not been up
there to look into the question of how. the faults behaved,
or anything of the sort. The district was so near Leeds,
and so near the district that Prof. Kendall had made his
own, that he thought the latter’s opinion as to how the
coal field ended up would be considerably more valuable
than anything that he (the speaker) could say about it,
and he did not propose to deal with the matter at all.
He should be exceedingly grateful if Prof. Kendall would
look into the matter of whether faults could be ignored.
That certainly was an important matter, and the only
answer that he could give was that, if they did ignore
the faults, the results came out as he printed them, and
that by ignoring the faults one found that there was no
necessity to make the contours crowd more into one part
than another. It seemed to him that that was the
answer—that up to a certain point, and down to a
certain scale, it was allowable to ignore faults in dealing
with those spot levels for getting contour lines.. He
hoped in course of time to present detailed portions of
the map, contoured as he had done the big one; but that
was a thing that would come afterwards, and the
contours now shown would, he thought, serve as an
introduction to tell one which portions of the whole area
were best worth one’s while to deal with in the matter.
It was a broad survey of the whole, and he took it that
the present portion of the paper was really a portion of
his education, in getting to know what there was in the
coal field and to what extent he could investigate it. He
hoped that Prof. Kendall would, at no distant time, tell
them more about his evidence for the great east and west
master fault which came on the north side of the coal
field. Prof. Kendall had said that in talking about
permian contours it was a long way to go from Selby up
to the Tees, and that it did not do to suppose that the
permian continued to wedge out all the way to the Tees.
The northern 'Selby borehole was only 1| miles from the
edge of his (Prof. Fearnsides’) map, and he had not
used that exterpolation to get any knowledge of
contours. There was a big piece, for which there was no
evidence available to him, and the lines had been dra-wn
just as simply as they could be. If Prof. Kendall could
give him a reference to any work dealing with contours
by Mr. Cosmo Johns or anyone else, he should be very
glad.'