Dr. Aubrey Strahan — Geology at the Seat of War. 73 



For obvious reasons it would be unwise to describe in detail the 

 problems which have arisen for solution at the Front, but it may be 

 legitimate to remind you that tunnels, unlike wells, should be so 

 designed as to keep clear of water, and that the best way of effecting 

 this object is to keep the operations within the limits of a watertight 

 formation, as was done in the case of the tube-railways. An 

 exhaustive study of the thicknesses and inclinations of the strata, and 

 especially of tbe faults or folds by which they are affected, is 

 required for the purpose. The necessary observations are not easy 

 to make, for the calm reflection required for the solution of a geological 

 problem is apt to be interrupted by the attentions of the enemy. 

 Operations are of necessity hurried and hazardous. It is well also to 

 endeavour to realize the conditions under which our men are working 

 in the tunnels. There is no branch of the Services, whether on 

 the sea or under it, on the ground or in the air, in which pluck and 

 endurance have not been manifested to a degree which would have 

 been scarcely credible two or three years ago. No less are these 

 qualities called for in the men who are working in the bowels of the 

 earth, with the ever-present danger of being forestalled by the 

 enemy and of being buried alive with no possibility of rescue. 



The Secondary and Tertiary formations rest upon an undulating 

 plane cut in the Palaeozoic rocks, conveniently known as the Palaeozoic 

 floor. These ancient rocks have been thrown in the course of 

 geological ages into the most complicated structures. Not only are 

 they folded, but along certain belts of country they have been 

 inverted and their newer members thrust bodily over their older 

 members. The plane therefore cuts across rocks of many ages, 

 ranging from Coal-measures to Cambrian or earlier. In the locating 

 of Coat-measures among these older rocks, under the blanket of 

 Secondary and Tertiary strata, lies the problem of extending the 

 coal resources of the country. 



The first step towards accomplishing this in the South of England 

 was taken in Kent, where the existence of Coal-measures was 

 anticipated on geological reckoning many years ago and proved in 

 1886. It was argued that the Axis of Artois, a belt characterized 

 by intense folding and overth rusting from the south, which ranges 

 past Liege, towards Douai and thence to the coast near Calais, must 

 continue through the South of England, and that there might be 

 coalfields entangled in it in England as on the Continent. 



The numerous borings put down in Kent since 1886 have had the 

 result of proving that the Coal-measures there lie in a trough in the 

 Carboniferous Limestone, the axis of which ranges in a north- 

 westerly direction. The dips observable in the cores are usually 

 gentle, and there is nothing to suggest faulting or folding such as 

 characterize the coalfields situated on the Axis of Artois. 



It therefore is still a matter of doubt whether the Kent Coalfield 

 is situated on that axis, and not to the north of it, and whether it 

 does not compare in this respect with the coalfield of La Campine. 

 This field was discovered in 1901, and twelve or more shafts were 

 being sunk through the Tertiary beds and the Chalk into the Coal- 

 measures when the War broke out. By some Continental geologists 



