222 



Mr. E. Hull on the Coalfields beneath [Dec. 15, 



December 15, 1870. 

 General Sir EDWARD SABINE, K.C.B., President, in the Chair. 



The Duke of Sutherland was admitted into the Society. 



The reading of the Report on Deep-sea Researches carried on during 

 the months of July, August, and September 1870, in H.M. Surveying 

 Ship 'Porcupine,' by Dr. Carpenter, F.R.S., and Mr. J. Gwyn Jeffreys, 

 F.R.S., was resumed and concluded. 



December 22, 1870. 



General Sir EDWARD SABINE, K.C.B., President, in the Chair. 



The following communications were read : — 



I. " On the Extension of the Coal-fields beneath the Newer Forma- 

 tions of England; and the Succession of Physical Changes whereby 

 the Coal-measures have been reduced to their present dimensions." 

 By Edward Hull, M.A., F.R.S., F.G.S., Director of the Geolo- 

 gical Survey of Ireland. Received November 30, 1870. 

 (Abstract.) 



In this paper the author, embodying with his own the observations of 

 previous writers on the physical geology of Great Britain, especially those 

 of Murchison, Godwin- Austen, Ramsay, Phillips, and the late Professor 

 Jukes, showed that the Coal-measures were originally distributed over 

 large tracts of England, to the north and to the south of a central ridge or 

 barrier of Old Silurian and Cambrian rocks, which stretched across the country 

 from North Wales and Shropshire into the Eastern Counties, skirting the 

 southern margin of the South Staffordshire Coal-field. This barrier, or 

 ridge, was a land-surface till the close of the Carboniferous period. 



To the north of the central barrier, the highlands of Wales, the moun- 

 tains of the Lake-district, and probably small tracts of the southern uplands 

 of Scotland formed land-surfaces skirting portions of the Carboniferous 

 area, while the Carboniferous tract to the south of the central barrier was 

 probably bounded by a land-surface trending along the southern coast of 

 England. The distribution of the Coal-measures at the close of the Car- 

 boniferous period was illustrated by a Map, No. 1. 



It was then shown that the whole Carboniferous area was subjected to 

 disturbances through the agency of lateral forces, whereby the strata were 

 thrown into folds along axes ranging (approximately) in east and west 

 directions ; and as denudation accompanied and followed these disturbances, 

 and acted chiefly over the arches (or anticlinals), large tracts were divested 

 of Upper Carboniferous strata, and thus the first phase in the marking out 

 of the limits of our present coal-fields was brought about. The effects of 

 these movements and denudations were illustrated by Map No. 2. 



The disturbances which ensued after the deposition of the Permian 



