34 



SCIENCE-GOSSIP. 



present covering of secondary rocks, we should find 

 this palaeozoic ridge pursuing a devious, though 

 generally east and west course, approximately 

 parallel to, but south of, the Thames and Kennet, 

 with coal measures on its flanks, preserved in 

 long narrow basins like those of Belgium. He 

 considered, moreover, that the superincumbent 

 secondary rocks would be found to thin out in 

 an eastwardly direction, and to rest upon this 

 palaeozoic floor at no great depth below the surface. 



It was not long before evidence was forthcoming 

 of the general soundness of Mr. Godwin-Austen's 

 views. On the advice of Mr. (afterwards Sir) 

 Joseph Prestwich, the Hampstead Water Company 

 had been boring at Kentish Town through the 

 tertiary strata and underlying chalk and gault of 

 the London Basin in order to tap the plentiful 

 supply of pure water which it was anticipated 

 would be reached in the Lower Greensand below. 

 Before Mr. Godwin-Austen's paper was printed, 

 the result of the boring came to hand, and proved 

 to be of a most unexpected character. His theory 

 of the thinning out of the secondary rocks in this 

 direction was more than realised. The whole of 

 the secondary rocks below the gault, including the 

 Lower Greensand, Wealden, Jurassic and Triassic 

 were found to be absent, for at 1,100 feet from the 

 surface, red sandstones and shales were met with, 

 which are now generally regarded as belonging to 

 the Devonian or Old Red Sandstone period, and 

 therefore antecedent to the Carboniferous. 



That Mr. Godwin-Austen's palaeozoic ridge had 

 been actually struck was soon confirmed by many 

 deep borings in the London basin, all undertaken 

 with the purpose of finding water. One at Cross- 

 ness, on the south bank of the Thames, reached 

 similar rock at about 1,000 feet down, but the 

 absence of organic remains again rendered the 

 determination of its age somewhat uncertain. In 

 1877 more positive evidence was forthcoming. A 

 boring for water to supply a brewery at the corner 

 of Tottenham Court Road and Oxford Street 

 encountered sixty-four feet of oolitic strata after 

 piercing the gault, and then at 1,064 Iee ' from 

 the surface entered upon dark-coloured shale, 

 dipping south at an angle of 40 degrees and 

 containing fossils of Upper Devonian age. Palaeo- 

 zoic rocks, probably Devonian, have also been 

 reached at Streatham and Richmond, at depths of 

 about 1,000 and 1,200 feet respectively. 



At Turnford, near Cheshunt, twelve miles north 

 of London, strata and fossils resembling those of 

 the Tottenham Court Road boring, and therefore 

 Upper Devonian, were met with at a depth of 9S0 

 feet, while the upper beds of the next older 

 formation — the Silurian — were found at a depth 

 of less than 800 feet at Ware, eight miles further 

 north. Here the beds dipped about 40 degrees 

 also, and probably to the south. 



At Harwich, dark slaty rock was struck below 

 the Gault about 1,000 feet below sea-level. A 

 fossil of doubtful character inclined Mr. Prestwich 

 to the opinion that this rock, was of Lower 

 Carboniferous age, but a recent careful micro- 

 scopical examination on the part of Mr. W. W. 

 Watts has induced the latter to reject the supposed 

 fossil as merely a peculiar fracture, and to refer 

 the rock on lithological grounds to some formation 

 older than the Carboniferous — probably Upper 

 Silurian. Similar palaeozoic rocks have been 

 recently found at a depth of about 1,000 feet at 

 Slutton and Weeley, a few miles to the west and 

 south-west of Harwich, and also at Culford, near 

 Bury St. Edmunds, at little more than half that 

 depth. 



It has thus been amply demonstrated that the 

 upper cretaceous rocks of the London Basin 

 repose on a palaeozoic floor at a depth nowhere 

 much exceeding 1 ,000 feet ; that north of the 

 Thames, at least, this floor is composed of beds 

 older than the Carboniferous, and that the general 

 dip of these old rocks is about forty degrees to 

 the south. The inference, therefore, is that with 

 Silurian beds under and to the north of Ware, 

 and Devonian under Cheshunt and London, there 

 is a strong probability that the Lower Carboni- 

 ferous will set in somewhat to the south of 

 London, and the coal measures still further south, 

 perhaps in the neighbourhood of the North 

 Downs or on the borders of the Wealden area. 



This inference has been considerably streng- 

 thened by the actual discovery of coal measures 

 near Dover a few years ago. For a long time 

 past the French miners have been extending their 

 operations in a north-west direction towards 

 Calais, following up the course of the Belgian 

 coalfield under the chalk by which it is ultimately 

 covered, until at the present time there are 

 collieries in full work within thirty miles of Calais 

 and fifty miles of Dover. A boring at Calais 

 revealed the still further extension of these coal- 

 fields towards our shores, and when, in 1S82, the 

 Channel Tunnel scheme was interdicted by the 

 Government, Mr. Francis Brady, engineer to the 

 Tunnel Company and the South-Eastern Railway, 

 suggested to the directors that the staff of men 

 retained to keep up the Tunnel Works might well 

 be employed in a test boring for coal. The 

 suggestion was adopted and crowned with success. 

 A shaft was sunk from the surface to sea-level — a 

 depth of 44 feet, from the bottom of which a bore- 

 hole 18 inches in diameter was begun on the 

 percussion system. After passing through 174 feet 

 of Chalk, 8 feet of Upper Greensand, 121 feet of 

 Gault, 241 feet of Lower Greensand and Wealden, 

 and 613 feet of Jurassic strata, coal measures 

 were reached at a depth of 1,157 f eet from the 

 surface, the first seam of coal met with being 



