1186 THE COLLIERY GUARDIAN. December 10, 1915. other boring record in Kent; and out of some 20 or more of such vertical sections in this field known to the writer, none even remotely resembles that of Stonehall in the number and thickness of the seams proved. A study of the record of this boring appears to him, however, to suggest grounds for very strong suspicion that not only has the boring gone through a number of small faults, thus repeating several of the seams, but that many seams, elsewhere very thin, have here increased to a quite abnormal thickness. With regard to the faulting, the writer suggests that in all probability the two higher seams of 7 ft. 2in., the two seams of 6ft. 4in., and possibly also the seam of 7 ft. 10 in. at 3,266 ft., and the seam of 8 ft. 7 in. at 3,545 ft., are all repeated by faults. These two considerations render it at present impos- sible to effect a correlation with any degree of certainty until further borings, which are urgently required around, and not far distant from Stonehall, throw light on these points. The writer thinks that it will then be possible to bring Stonehall into line both with the Waldershare and other borings still further north, and also perhaps with Shakespeare Cliff. With Maydensole, however, there is and could be no agreement: for, while a large part, perhaps the whole, of the Stonehall cores belong to the transition coal measures, only the higher 1,156 ft. of the measures at Maydensole belong to that horizon,* and the coals of these series show no similarity to those at Stonehall. Passing now to the Chilton boring, the strike line of which lies only about a mile to the south of that of Stonehall, on a hypothesis of unfaulted and unfolded ground existing between these two borings, the Chilton boring is only intelligible on the supposition that the higher part lies considerably above any measures proved at Stonehall, and that the Chilton boring ended at a point above the level of the first really thick coals proved at Stonehall. This may be the case; but, until further borings have been made, there will be no proof of the fact. On the other hand, there is already much to be said for the view that the structure of the coal measures around Chilton and Stonehall is very far from simple. The only other borings lying further south than Chilton (of which the records have been published) are those of Ellinge and Shakespeare Cliff. The former may be neglected; with the latter Chilton does not agree, although the distance between their strike lines is only a little over two miles in length. These cases present another illustration of the neces- sity for further borings, which the writer has already pointed out in his former paper. This ground is not yet sufficiently proved, so far as the coal seams are con- cerned, and any attempt to sink to coals, without having previously proved their thickness in every direction in which it is proposed to work them, will in such a coal field as Kent only end in disaster. The Bourne (Bishopsbourne) Boring. The Bourne (Bishopsbourne) boring is situated about 100 yds. from the main Canterbury-Dover road on Barham Down, along the lane leading south-west to Bishopsbourne church. It lies on the left-hand (south) side of the same lane, and close to it, and 100 yds. north- east of the entrance to Bourne Park, about half-way between the stream running through that park and the above-mentioned main road. It is distant four miles to the south-east of Canterbury. The nearest borings on the coal field are Trapham, under four miles to the north-east; Fredville and Snowdown, 3| miles to the south-east-east; and Ropersole, 3| miles south-south- east. The boring was begun on February 27, 1913, and finished on January 8, 1914, the total depth bored being 3,235 ft. The contract was carried out by a Belgian firm, the Tr^for Company, of Brussels. The top of the boring was 176 ft. above Ordnance datum. The mesozoic cover was 1,313 ft. thick (1,137 ft. being below Ordnance datum). The coal measures were 1,856 ft. thick, the top of the coal measures being 1,313 ft. from the surface, or 1,137 ft. below Ordnance datum. The carboniferous limestone was proved at 3,169 ft. from the surface (2,993 ft. below Ordnance datum), and 66 ft. of this rock was penetrated. Thirty-one seams in all, mostly very thin coals, were proved, three being split coals. Of the 28 coals— 12 were less than 1 foot thick. 7 „ between 1 ,, and 2 feet thick. 6 „ „ 2 feet ,, 3 ,, 2 „ „ 3 „ „ 4 „ 1 exceeded 5 „ in thickness. The following were the three thickest seams :— Coal seam. Depth from surface. Ft. in. Ft. 3 6 .................. 1,504 3 11 (split) ........... 2,806 5 10 „ 2,838 The fossil plants showed that the upper section of the coal measures belonged to the transition coal measures, and the lower section to the middle coal measures; but the evidence was insufficient as to exactly what thickness of the measures proved belonged to each horizon. Pro- bably the transition coal measures were about 800 ft. thick, and the middle measures about the same. Out of 1,856 ft. of measures, 667 ft. of sandstones occurred, or about 36 per cent., the rest of the beds being shales, fireclays, and other argillaceous rocks. Remarks on the Bourne Boring. The Bourne boring is the westernmost on the coal field of which the record has been published. It is obvious that the sequence of the measures here (1,856 ft.) is much shorter than might have been expected. Both horizons are present, and the palaeo- botanical evidence shows that the highest 800 ft., or thereabouts, undoubtedly belong to the transition coal *Arber, E. A. N., ibid., 1914, p. 701. measures. Whether the remaining 1,056 ft. are all middle coal measures, or some smaller thickness only, is uncertain. This boring is obviously affected by one or more powerful faults. It appears to have started somewhere on the level of the Snowdown thick coal, but a very large proportion of the normal sequence of the measures, particularly of the middle coal measures, has been faulted out. Where these faults cut the section is as yet uncertain, for this boring is very isolated. The lower part, however, does not correspond with the Trapham section, and thus it appears probable that the fault or faults affect this region in particular. This faulting is no doubt connected with proximity to the western boundary of the field, which does not lie more than a few miles to the west of the Bourne Depth from Surface F«g 4 - Fleet (ash level) Boring Thickness ’90S- 19S6- 1599 -- FEET 1225-- 1090 FEET INCHES - 3 -3 O 1384- 1406 - 1464 — 1485 — 1515 — 1 534- 1550-1 173 7 17 02 1 7 76, 1787: 1798. 1801- 1844 CARBONIFEROUS LIMESTONE boring. The writer is still of the opinion expressed in his former paper* that, to the west, the measures are probably faulted out completely, and that no natural outcrop occurs in this direction. The Fleet (Ash Level) Boring. The Fleet or Ash Level boring is situated on the borders of Ash Level, a little to the west of Richborough Castle. It lies on and close to the eastern side of the lane (Cooper’s Street Drove) that runs north from Cooper’s-street, but before reaching Fleet Farm, and about midway between these two points. The nearest boring to the north-east is Ebbsfleet, 1| miles distant; to the south-east, Mattice Hill, HYTMEa * CANTERBURY ELHAFUj HtANt. » BlSMOPSBOORMt mbehTon *vrir»CHAM JLKESTOnE J4ALKHAN • I 3AN0WICH 4« MNCSTtR iirER BRCAD5TA.IR9 JAMSGATE a 'xmarqate Ipeal 3KMJTH FORELAND Fig. 5.—Map of the Kent Coalfield, Showing the Positions of the New Borings. 1. The Chilton boring. 2. The Stonehall boring. 3. The Bourne boring. 4. The Fleet boring. The dots indicate the position of the other borings and sinkings, the records of which have already been published. 2| miles distant; to the south, Woodnesborough, 2| miles distant; and to the west, Walmestone, over 3 miles distant. The boring was begun on August 18, 1913, and finished on December 29 of the same year, the total depth being 1,966 ft. 7 in. The contract was carried out by a Belgian firm, the Trdfor Company, of Brussels. The top of the boring was 25 ft. above Ordnance datum. The mesozoic cover was 1,090 ft. thick from the surface (1,065 ft. below Ordnance datum). The coal measures were 819 ft. thick. The top of the measures were * Arber, E. A. N., 1914, ibid., p. 693. 1,090 ft. from the surface (1,065 ft. below Ordnance datum). The carboniferous limestone was proved at 1,908 ft. from the surface, or 1,883 ft. below Ordnance datum, 58 ft. of which rock was proved. In all there were 17 seams proved, most of them being thin coals. Of these— 3 were less than 1 ft. thick. 8 „ between 1 and 2 feet thick. 2 „ ,, 2 ,, 3 „ „ 2 ,, ,, 3 ,, 4 ,, ,, 1 exceeded 4 ft. m thickness. 1 „ 7 „ The thickest scams were as follows :— Coal seam. Depth from surface. Ft. in. Ft. 3 1 ’1,446 3 1 1,485 4 3 ......................... 1,515 7 2 ......................... 1,776 The fossil plants showed that the whole thickness of the coal measures belonged to the middle coal measures. Of the associated sediments, 198 ft. out of 819 ft. were sandstones, or less than 25 per cent. Remarks