228 report — 1879. 



M. Dewalque added : ' Starting from the supposition that our (Belgian)' 

 old strata are prolonged westward into England, and from the fact that 

 Upper Devonian strata occur under London, we are led to admit that the 

 band of Silurian slates of the Ostende boring must pass north of London. 

 These slates, which are referable to those of Tubise, must be separated 

 from Upper Devonian by other beds, such as the black slates of the Menin 

 shaft, which are Silurian. Considering the geographical position of 

 these three places, together with the east and west direction of our older 

 formations, it would not seem that their prolongation into England would 

 carry them sufficiently north of London, so that the Devonian beds there 

 should represent our Oondros basin, and not that of Namur. 



' If then at that place (London) we are in a prolongation of the Namur 

 basin, the strata at Meux's must dip south ; consequently, it is most 

 probable that the Coal-measures are to be found at a short distance 

 south.' 



Such were the inferences drawn by M. Dewalque in 1878 from the 

 result of boring at Messrs. Meux's. 



It may be stated that at the several places named, the Palaeozoic strata 

 reached were, at Ostende, Silurian ; at Menin, Silurian, like the strata at 

 Gambloux ; at Laeken, also Silurian. 



The supposition that the Silurian strata met with at Ostende would, 

 in their course westward, pass north of London has been proved by the 

 occurrence of beds of "Wenlock age at Ware, near Hertford, twenty miles 

 north of London. This discovery has come most opportunely to supply 

 the information which, only a year since, was needed as to the dip of the 

 Upper Devonian strata at Messrs. Meux's. 



The succession of the Palaeozoic strata, on this the English side of the 

 Channel, even into the far west, is just what it is in Belgium and the 

 north of France. From Brussels and Ostende, from north to south, the 

 successive members of the series mostly rise to the surface, and are 

 exposed in all the valleys of denudation extending north from the line of 

 the Coal-measures, as long since laid down by Dumont. 



With this guidance, and in spite of little as yet known with respect to 

 our own underground structure on the south-east, it can be safely put in 

 relation with what obtains on the European continent for an extent of 

 400 miles. The order in which the successive members of the Palaeozoic 

 series rise to the surface from beneath one another there, may be taken as 

 our guide as to the order and relation of the Upper Devonian at the end 

 of Tottenham Court Road and Oxford Street, and the section at Ware. 



The question of the strike and direction of the dip of the beds at 

 Meux's is now determined as forming part of the northern base of the 

 trough, containing first the mountain limestone series, and next, above, 

 the true Coal-measures. 



For practical guidance one point alone remains to be considered: from 

 the place of the Upper Devonian strata in the heart of London, what must 

 be allowed for the breadth of the outcrop of the mountain limestone 

 series, next in sequence ? 



In parts of Belgium the mountain limestone has been estimated as 

 600 feet thick ; it is less than that in easterly and westerly directions. 



The nearest place to London at which this is exposed is on the north 

 of the Boulonnais denudation, where, with its associated beds, it may be 

 put at 600 feet. The breadth of such a mass at its outcrop, and with an 

 angle of 30 to 35 degrees, such as the Devonian beds at Meux's had, would 



