The Kent Coal-field. 43 



2. December 3, 1913.— Dr. Aubrey Strahan, F.R.S., President, 

 ia the Chair. 



The following communications were read — 



1. "A Contribution to our Knowledge of the Geology of the 

 Kent Coal-field." By Dr. E. A. Newell Arber, M.A.^ F.L.S., 

 F.G.S. 



In this paper an attempt is made to give a general and connected 

 account of the Carboniferous rocks of Kent, based on the evidence 

 of some nineteen borings or sinkings. The Mesozoic cover of this 

 wholly concealed coal-field is ignored. It is shown that the proved 

 area is 200 square miles (128,000 acres), partly lying beneath land, 

 and partly beneath the North Sea, the Straits of Dover, and the 

 English Channel. The general strike is about 30° south of east 

 and north of west, and the dip of the Transition Coal-measures is 

 2° to 3° in the two localities where reliable evidence is alone 

 available on this point. 



The area, as a whole, is a syncline, limited on the north and 

 south by Armorican folds, of which the northern has been now 

 fairly accurately located. There is evidence also of a fold on the 

 east; and it is maintained that the Kent Coal-field is not continuous 

 with that of the Pas de Calais. There are reasons for believing 

 that the western boundary is a great fault. 



The chief surface feature of the Coal-measures is that of an 

 inclined plane, sloping rapidly but regularly westwards and south- 

 westwards from an elevated region near Ripple and Deal in the east. 



The Lower Carboniferous rocks exceed 450 feet in thickness, and 

 were denuded before the Coal-measures were deposited. 



The Coal-measures consist of the Transition Series (1,700 to 

 2,000 feet thick), and the Middle Coal-measures (2,000 feet). No 

 Lower Coal-measures or Millstone Grit occur. The measures are 

 grey throughout, and no red rocks, Espley rocks, ^^/rorJ/s-limestones, 

 nor igneous rocks occur. 



The coals are well distributed, and are often of considerable 

 thickness, although there is a frequent tendency to splitting and 

 inconstancy. Steam and household coals predominate, but gas coals 

 also occur. 



The most productive portions of the measures are the higher part 

 of the Transition and the lower part of the Middle Coal-measures. 



2. "On the Fossil Floras of the Kent Coal-field." By Dr. E. A. 

 Newell Arber, M.A., F.L.S., F.G.S. 



The floras of ten further borings in Kent are here recorded, and 

 the number of species known from the Kent Coal-field is raised to 

 96, as compared with 10 known in 1892 and 26 in 1909. A number 

 of the more interesting records are described and figured, some of 

 them being new to Britain or not previously found on the horizons 

 in question. 



As regards the horizons present in Kent, the plant-remains 

 indicate that, in the area so far proved, only Middle or Transition 

 Coal-measures, or both, occur. 



