106 SCIENCE PROGRESS. 



Again the coal-fields of Southern England probably have a 

 fairly symmetrical distribution on either side of the Mendip 

 axis. But in Central England the case is different. It can- 

 not be assumed that the Pennine Chain and the correspond- 

 ing supposed anticline to the east of the Northumbrian 

 and Yorkshire coal-fields run south to join the easterly 

 continuation of the Mendip ridge, for their course would 

 probably be profoundly modified by the existence of the old 

 pre-carboniferous ridge running in a general east and west 

 direction through Central England, which caused the ab- 

 sence of the lower carboniferous beds in that area. Such a 

 barrier would certainly affect the subsequent folding, and as 

 a consequence of it we actually see a marked want of sym- 

 metry in the arrangement of the exposed coal-fields of the 

 midland counties. This want of symmetry might well, and 

 probably would, extend to concealed coal-fields. Now the 

 central ridge, according to Professor Green and others, 

 should extend towards Bury St. Edmunds, and the old rocks 

 of the Culford boring may be a portion of it. If this be the 

 case, it would be very hard to predict the probable position 

 of coal-fields in East Anglia, and indeed it seems to the 

 writer that nothing short of an extensive series of borings 

 can settle the question, and that advice as to the stations 

 where borings should be tried is valueless, except in so 

 far as it concerns the possible approximate thickness of 

 rocks overlying the Palaeozoic floor. The influence of this 

 central ridge would not affect the old rocks south of the 

 Ardennes-Mendip axis, and this seems an additional 

 reason for advising trials to the south rather than to the 

 north of that ridge. In the meantime the thanks of geolo- 

 gists are due to those who are patiently collecting the 

 records of all borings and gradually aiding us in our restora- 

 tion of the old buried palaeozoic floor of South-eastern 

 England. 



BIBLIOGRAPHY. 



(i) SOMERVAIL, A. The Origin and Relations of the Lizard 

 Rocks. Trans. Roy. Geo/. Soc, Cornwall, vol. xi., pt. viii., 

 P- 536. 



