V 

 Mr. Whitalve/s Address to the Geological Section. 469 



depths of 378^ and 401 feet ; but these rocks seem to be only 

 boulders in a Jurassic clay : their occurrence, howevei', is suggestive 

 of the presence of older rocks at the surface no great way off, in 

 Middle Jurassic times. 



Much further northward, at Scarle, south-west of Lincoln, the 

 older rocks have been reached at the depth of about 1,500 feet, all 

 but 141 of which are Trias, and they begin with the Permian 

 (which crops out some eighteen miles westward), the Carboniferous 

 occurring after another 400 feet, and having been pierced to 130. 



We have then evidence that over a large part of South-eastern 

 England, reaching northward and westward of the London Basin, 

 though the older rocks are hidden by a thick mantle of Jurassic, 

 Cretaceous, and Tertiary beds, yet they seem to be rarely at a depth 

 that would be called very great by the coal-miner. They are 

 distinctly within workable depths wherever they have been reached. 



There is no area of old rocks at the surface in our island, south 

 of the Forth, in which Coal-measures are not a constituent formation. 

 Truly, further north, in the great tract of Central and Northern 

 Scotland there are no Carboniferous I'ocks ; but we can hardly say 

 that none ever occurred, at all events in the more southern parts. 

 We know, though, that on the west and north Jurassic and Triassic 

 beds rest on formations older than the Carboniferous. 



It is not, however, to this more northern and distant tract that we 

 should look for analogy to our underground plain of old rocks ; 

 rather should we look to more southern parts, to Wales and to 

 Central and Northern England, where Coal-measures are of frequent 

 occurrence. On the principle of reasoning from the known to the 

 unknown, I cannot see why we should expect anything but a like 

 occurrence of Coal-measures, in detached basins, in our vast under- 

 ground tract of old rocks. 



What, then, is the evident conclusion from what we know and 

 from what we may reasonably infer? Surely that trials should 

 be made to see if such hidden coal-basins can be found. 



One trial has been made, and it has succeeded : the Dover boring 

 has proved the presence of coal underground in Eastern Kent, along 

 the line between the coal-fields of South Wales and of Bristol 

 on the west, and those of Northern France and of Belgium on the 

 east. 



The long gap between the distant outcrops of the Coal-measures 

 near Bristol and Calais has been lessened very slightly by the 

 working of coal under the Triassic and Jurassic beds near the former 

 place, but much more by our brethren across the narrow sea, the 

 extent of the Coal-measures beneath the Jurassic and Cretaceous 

 beds, having not only been proved by the French and the Belgians 

 along their borders, but the coal having been largely worked. At 

 last, we too have still further decreased the gap, by the Dover 

 boring, a work that I trust is to be followed by other work along 

 the same line. 



But is this the only line along which we are to search ? Are 

 we to conclude that the only coal-fields under our great tract of 



