1314 THE COLLIERY GUARDIAN. June 12, 1914. on gas coming into a workman's place, it was not observed by any indication on the electric lamp, and in consequence the man was overcome and died. The management at once stipulated that in every working place where electric lamps were used there must always be a spare safety lamp; but a few days afterwards a heavy blower of gas came out suddenly whilst work was in progress, the gas immediately extinguished the safety lamp, and the men just managed to escape with their lives. There is no doubt that, owing to the superior light given by the electric lamp, great help can be gained by the miner in the examination of the mine, but the law should have provided by the statutory rules that the liability of danger arising under this head should have been obviated, which was clearly known when the rules were made. In regard to the re-lighting of safety lamps under- ground, the 1911 Act (section 34, iii.) permits the unlocking of lamps and re-lighting at lamp stations, and within a short time of the Act becoming law, occurred the explosion at Senghenydd Colliery, in which 449 lives were lost. The conclusions arrived at after the enquiry •suggest that the explosion may have originated by a The Geology of the Kent Coalfield. By E. A. NEWELL ARBER, M.A., Sc.D., F.G.S., Trinity College, Cambridge, University Demonstrator in Palaeobotany. From a paper read before the Institution of Mining Engineers, London, June 4, 1914. (Concluded from, page 1244.) The Contours of the Palaeozoic Floor. In considering the contours of the palaeozoic floor of Kent, the writer will confine his attention-solely to that portion of the county which is known to be occupied by ■carboniferous rocks. The wider question of the nature of the surface of the palaeozoic floor of Southern and South-Eastern England has been recently dealt with by Dr. A. Strahan, and, in the case of the Southern Mid- lands and Eastern Counties, by Dr. A. M. Davies and Mr. J. Pringle. The carboniferous floor of Kent possesses one well- marked feature. There is a ridge or plateau of high land in the east, in the neighbourhood of Ripple and Deal, and on the west and south-west there is a gradual but rapid lowering of elevation by as much as 500 ft. in a distance of some eight miles, as far as Ellinge. In the extreme north-eastern corner of the coal measure area, so far proved under land, there are indications of low- lying ground at Ebbsfleet, with a rapid rise southward, -of 300 ft., to the same plateau of Deal. In the north- west, not very far from Stodmarsh and Canterbury, there is another elevated region, from which the ground slopes rapidly southwards, with a drop of 350 ft. in about 11 miles to Ellinge. The order in the list which follows, although based upon the depth below Ordnance datum, is roughly an east-to-west arrangement :— Height of Top of Coal Measures Below Ordnance Datum. Feet below No. Boring or sinking. Ordnance Datum. 1. Ripple ........................ - 808 2. Oxney .........:............... - 859 3. Maydensole .................... — 941 4. Tilmanstone sinking............ — 947 5. Mattice Hill (Sandwich) ....... — 964 6. Walmestone..................... —1,002 7. Woodnesborough............... —1,017 8. Barfreston..................... -1,031 9. Goodnestone.................... — 1,052 10. Waldershare.................... —1,059 11. Trapham (Wingham).............. -1,065 12. Shakespeare Cliff sinking...... —1,100 13. Fredville...................... -1,116 14. Ropersole ..................... —1,180 15. Ellinge........................ -1,286 In the north there are two further borings :— Ebbsfleet ................... —1,098 Stodmarsh ................... — 979 In the sketch map the writer has endeavoured to trace the 50 ft. contours provisionally. These, so far as can at present be seen, prove to be fairly regular, although it must be remembered that the boring records are liable to err by as much as 10 ft., or even more in some cases. The absence of sufficient borings as yet in certain direc- tions further tends to make the contour lines appear more regular than in all probability they actually are. That the old palseozoic floor of Kent will, when it is better known, exhibit features which may be safely attributed to the accidents of the denudation to which it had long been subjected before the mesozoic cover was laid upon it, is not to be denied. But, so far as the broader features alluded to above are concerned, the writer fails to see how they are to be explained on these grounds. It is known that the gradual slope from Deal and Ripple to the south-west extends far in a westerly direction, and this is as true of the pre-carboniferous as of the carboniferous ground. At Brabourne the Devonian occurs at 1,706 ft. below Ordance datum, and the writer therefore concludes that some more pro- found significance attaches to these facts. The Carboniferous Rocks. Both upper and lower carboniferous rocks are present in Kent. A study of the former has shown that only two palaeobotanical horizons are represented by these sedi- ments, the transition coal measures and the middle coal measures. The middle coal measures in Kent rest unconformably on the lower carboniferous. There are no indications either of upper or of lower coal measures, nor of millstone grit; and none of the basal beds of the coal measures in Kent have any lithological resemblance to the millstone grit of the Pennine coalfields. blower of gas issuing from a heavy fall of stone, and igniting itself at the underground naked light lamp station. The Home Office, through its representative, states that, “ it is inadvisable, to say the least, to permit the opening of a safety lamp in any mine of a gassy nature such as Senghenydd, and there are many mines of a similar character not only in South Wales, but in other parts of the United Kingdom.” When the 1911 Act was being compiled, it was well known to the Home Office, through their inspectors, that at some of their best-managed and most gassy collieries rules were in force that no safety lamp was ever allowed to be unlocked or re-lit underground on any pretext what- ever, and that sufficient spare safety lamps w’ere taken into each district every day ready lit, and placed in a locked wire cage, ready for emergency in case of a man losing his light. Why, then, should not this precaution have been brought into vogue long ago under section 30 of the 1911 Act, and statutory provision made for carrying into effect what is now expressed after a disaster of this magnitude has occurred, as a dangerous practice, when such facts were clearly known before- hand. It is not possible to decide at present the location of the highest beds in the field, that is, the position of the major axis. The relationship of the measures proved at Shakespeare Cliff to those at Waldershare, and to the borings and sinkings still further north, is unknown. But, omitting Shakespeare Cliff, and also the measures at Ellinge and Ropersole, the horizon of which is unknown, the upper part of the Waldershare boring certainly appears to lie higher than the measures proved at any of the other borings. The borings and sinkings in the central region of the coalfield have, for the most part, penetrated only the transition measures; but, on passing northward and eastward, these beds thin out, and may even disappear, and only middle coal measures are found. This is shown in the following table (wherein the borings are arranged from south to north), and include all the borings the horizons of which are known :— Thickness of the proved Coal Measures of Fourteen Borings in Kent. Transition Middle Total No. Boring. m coal Leasures. coal measures. coal measures. 1. Shakespeare Cliff Ft. + 1,170 . Ft. 0 .. Ft. . +1,170 2. Oxney 778 . .. 1,947 .. . 2,705 3. Maydensole 1,156 .. . +1,409 .. . +2,565 4. Waldershare + 1,469 . 0 .. . +1,469 5. Ripple 518 . .. 1,769 .. . 2,287 6. Barfreston 1,614 . .. +489 .. . +2,103 7. Fredville + 460 . 0 .. . +460 8. Goodnestone 312 . .. +1,406 .. . +1,718 9. Woodnesborough 0 . .. 1,549 .. . 1,549 10. Mattice Hill (Sandwich) 0 . .. 1,076 .. . 1,076 11. Trapham (Wingham) ... 0 1,651 .. . 1,651 12. Walmestone 0 . .. 1,201 .. . 1,201 13. Stodmarsh 0 . .. 1,075 .. . 1,075 14. Ebbsfleet 0 . 103 .. 103 In the foregoing table the plus sign (+) indicates that the full extent of the beds was not proved, the boring ending still in coal measures. It should also be remarked that the thickness in the first two columns are not accurate in cases where both the transition and the middle coal measures are repre- sented in the same boring; for it is impossible, by means of fossil plants, to determine the boundary between two zones within several hundred feet of pos- sible error, since the flora of the one is a true transition to that of the other. The carboniferous limestone series has been proved in many borings to the north and east, as recorded below : List of Places at which the Carboniferous Lime- stone Series has been proved on the North and on the East. Thickness of No. Boring. carboniferous limestone. Ft. 1. Oxney .................... + 40 2. Ripple ................... +147 3. Woodnesborough............ + 12 4. Mattice Hill (Sandwich) .. + 24 5. Trapham (Wingham) ........ +450 6. Walmestone ............... + 9 7. Stodmarsh ................ +121 8. Ebbsfleet................. + 230 In no case has the limestone series ever been pene- trated completely. The writer’s colleague (Mr. Henry Woods) has examined the fauna of the Trapham and Stodmarsh limestones, the only horizons at which the writer could find fossils sufficiently abundant and well- preserved to permit of the zones being determined. Mr. Woods has concluded that at Trapham the Dibuno- phyllum and at least part of the Seminula zones are absent, while the Syringothyris zone is represented. In the Stodmarsh boring, on the other hand, Mr. Woods finds that either the Seminula or the lower part of. the Dibunophyllum zone is represented, a higher horizon than at Trapham. At Ebbsfleet Dr. Strahan has already shown that the zone there present is the same as at Stodmarsh. The Coals. From a study of many coalfields in Great Britain and Ireland, the writer has arrived at the conclusion that they fall into two main types : (1) Those in which the coals are, speaking generally, constant in thickness and of wide lateral distribution, showing but rarely any signs of splitting; and (2) those in which the great majority of the coal seams split as traced laterally, and are typically of inconstant thickness and distribution. The Forest of Dean and Yorkshire coalfields are examples of the former class, and the Newcastle coal- field is an excellent illustration of the latter. The great characteristic of the Kent coalfield is the frequent splitting, and the thickening or thinning of many of the seams when followed laterally. It thus falls into the second category, and in many respects resembles the Newcastle coalfield. One result of this inconstancy in the thickness of the Kentish coals is that it naturally makes the correlation of the seams met with in the different borings a matter of great difficulty. Thus the structure of this wholly concealed coalfield is rendered all the more obscure. The writer does not propose to publish his working hypothesis on the subject in full at present. Many of the borings are several miles apart, and, in such cir- cumstances, doubt as to the correlation must naturally remain, until further intermediate records are available. He may, however, briefly allude to' the main provisional conclusions at which he has arrived, with the admission that some of them may well require modification in future. While there is no one main, dominant “ thick coal,” the seams are fairly evenly distributed throughout the measures, with the exception of the lower part of the transition and the upper part of the middle coal measures. In this region only a few, very thin, coals are usually met with, while in some borings only a long stretch of entirely barren ground occurs. In one case this barren portion is nearly 800 ft. thick, although this is exceptional. The thickest transition coals, so far as the coalfield has as yet been explored, lie near the top of these measures. The chief seam, which is now being worked at Snowdown and Tilmanstone collieries, was recorded in the Barfreston boring as being 6 ft. lin., and at Waldershare as 5 ft. 2 in. thick. At Snowdown it is 4 ft. 4 in. thick, with a tendency to partings, and at Tilmanstone, including two partings, the total thickness is 5 ft. 2 in. Fig. 2.—Contour Map of the Coal-Measures of Kent. Scale, 4 Miles to 1 Inch. Measurements of Depth indicated in Feet below Ordnance Datum. Two higher seams 3 ft. 4 in. and 4 ft. 6 in. thick respectively occur at Waldershare; and, in the Bar- freston boring, below the coal which is at present being worked at Tilmanstone, many small coals occur, either split or up to 4 ft. in thickness. In regard to the split coals, it must be remembered that it is highly probable that, in some locality or other the components will come together and form a solid seam of workable thickness. Apart from this fact, many of the lower transition coals are of workable thickness in one region or another. It has not yet been found possible to determine in detail the directions in which the splitting chiefly takes place in Kent. In the middle coal measures the thickest seams, up to 11 ft., or more, occur near the base of the series, and there are often several other coals, more than 4 ft. thick, in this region. In fact, there appear here at least three, perhaps four or more, really thick seams, near together, although these coals are just as liable to split as those in the transition measures. A little higher up several important but usually thinner coals also occur, and in some borings there is a seam from 4 ft. to 6 ft. thick in a still higher position. The middle coal measures undoubtedly possess a larger number of thicker coals than the transition measures, and while the thickest of these lie near the base, the higher “ middle coals ” are more abundant, and usually thicker and better distributed than in the