44 Proceedings. 



firmed by a boring at Harwich, in which a black slatey rock 

 of the Carboniferous period was found immediately below the 

 Gault. A sinking also at Kentish Town is farther proof; the 

 Lower Greensands, and also all the Oolitic series, being 

 absent. And Mr. Prestwich acknowledges the evidence that 

 there is under the central part, at all events, of the London 

 Tertiary area a tract or ridge of old rocks immediately under- 

 lying the Chalk or Gault, on different portions of which the 

 wells of London and Harwich have touched ; the one on the 

 Old Eed Sandstone, and the other on the Carboniferous for- 

 mation ; and that these old rocks at London and at Harwich 

 both belong to the rocks of the Mendips and the Ardennes. 

 In 1877 more light was thrown on the question by a boring 

 at Meux's Brewery, in Tottenham Court Koad, where rocks 

 older than the Coal-measures were found immediately under 

 the Secondary Rocks, at a depth of 1100 feet. In 1860, Sir 

 N. N. Smith, after a short description of the Coal-measures 

 under Cretaceous beds in the North of France, said : — " A 

 comparison of these features with those exhibited on the 

 flanks of the Mendip Hills, and an observation of the under- 

 ground course of the sharp trough of French Coal strata, 

 inclines ns to the speculation that the Primary Rocks may be 

 continuous from the Severn to the Rhine." In 1871, 

 Professor Prestwich writes, " Should the Coal-measures again 

 set in to the westward of Calais (that is, m England) they 

 would be found equal in productiveness to the great Coal- 

 fields of the North of France and Belgium." That they do 

 so set in is now clearly shown by their discovery at Dover. 

 He also says, " Everywhere along the old tract of Carboni- 

 ferous and Devonian Rocks, from Westphalia to South Wales, 

 there appears to have been an old growth of Coal-producing 

 vegetation of great luxuriance and persistence ; everywhere 

 along the immediate flanks of the great axis traversing that old 

 tract we find rich and productive measures, however much 

 they may deteriorate as they recede from that line, and there 

 is no reason to believe but that we should find the same 

 productiveness along the flanks of the same underground 

 ridge, although at a distance of 20 or 30 miles from it a 



