1890.] on the Search for Coal in the South of England. 177 



Belgium the Cretaceous deposits rest immediately upon the waterworn 

 older rocks. 



From these general considerations it is clear that the coal-measures 

 which formerly extended over nearly the whole of Southern England 

 can now only be met with in isolated basins under the newer rocks, 

 and that these are thinnest along the line of the above-mentioned 

 barrier. 



4. The exposed coal-fields in Britain, and on the Continent also, 

 Godwin-Austen pointed out, along this line, are of the same mineral 

 character, and the pre-Cavboniferous rocks are the same. This ridge 

 or barrier also, where it is concealed by the newer rocks, is marked 

 by the arch-like fold (anticlinal) of the chalk of Wiltshire, and by 

 the line of the North Downs in Surrey and Keut. Godwin-Austen 

 finally concluded that there are coal-fields beneath the Oolitic and 

 Cretaceous rocks in the South of England, and that they are near 

 enough to the surface along the line of the ridge to be capable of 

 being worked. He mentioned the Thames valley and the AVeald of 

 Kent and Sussex as possible places where they might be discovered. 



These strikingly original views gradually made their way, and in 

 the next eleven years became part of the general body of geological 

 theory. They were, however, not accepted by Sir Eoderick Murchison, 

 the then head of the Geological Survey, who maintained to the last 

 that there were no valuable coal-fields in Southern England. 



5. The next important step in the direction of their verification 

 was that taken by the Coal Commission of 1866-67, by whom 

 Mr. Godwin- Austen was examined at length, and the results of the 

 inquiry embodied in the Eeport by Mr. JPrestwich. In the Report 

 Mr. Godwin-Austen's views are accepted, and fortified by a vast 

 number of details relating both to the coal-fields of Somersetshire and 

 of France and Belgium. Mr. Prestwich also calls special attention 

 to the physical identity of the coals of these two regions, and to the 

 fact that the Carboniferous and older rocks in both are similarly 

 disturbed. He concludes, further, that the coal-fields which now lie 

 buried beneath the newer rocks are probably equal in value and in 

 extent to those which are exposed in Somerset and South Wales on 

 the west, and in Belgium and France on the east. 



We will now proceed to test these., theoretical conclusions by the 

 light of recent observations. 



6. The coal-fields of Somerset and Gloucester were proved by the 

 labours of Prof. Prestwich and the Coal Commission of 1866-67 to be 

 small fractions of the great coal basin which lies buried beneath the 

 Triassic, Liassic, and Oolitic rocks, from the Mendip Hills northwards 

 past Bristol to Wickwar. On the west also three small isolated 

 coal-basins occur — those of Nailsea and Portishead, which are par- 

 tially, and that of Aust, which is wholly, concealed by the newer 

 rocks. The coal-measures are folded and broken, and traversed by- 

 great " overthrust " faults, which at Kingswood give the same series 

 of coals twice over in the sinkings of one colliery. Their southern 



Vol. XIII. (No. 84.) n 



