AUSTEN EXTENSION OF THE COAL-MEASURES. 73 



of the restoration of the original surfaces which supported the coal- 

 vegetation. 



2ndly. That the Permian and Triassic groups indicate the earhest 

 changes which the form of this area experienced. 



3rdly. That at an early time a line of disturbed surface was pro- 

 duced, having a general E. and W. direction, and which, traversing a 

 portion of the area of the coal-growths, has placed all the members 

 of that series along its course either at or near the present surface. 



4thly. That the physical and geological evidence derived from 

 the S. of England concurs in showing that this area has followed 

 these changes, and been a part of the zone along which all those 

 movements have taken place which have tended to preserve the 

 great Franco-Belgian coal-band and render it available. 



The present communication must be considered only as a first 

 attempt ; but it is one which, from its economical importance, cannot 

 fail to attract attention in proportion as the extension of productive 

 coal-measures becomes proved from Therouanne eastwards : it will 

 not be deemed too much to say, that we have strong a-priori reasons 

 for supposing that the cowse of a band of coal-measures coincides 

 withy and may some day he reached, along the line of the valley of 

 the Thames, whilst some of the deeper-seated coal, as well as certain 

 overlying and limited basins, may occur along and beneath some of 

 the longitudinal folds of the "Wealden denudation. 



What is now above measure needed is, that we should obtain one 

 single point of verification as to the depth at which any part of the 

 Palaeozoic group occurs beneath our S.E. area : the state of the 

 question is such, that from this one single point, once ascertained, 

 the rest of the investigation might be conducted, for practical pur- 

 poses, with perfect certainty, and it is therefore of importance that 

 the question and its possible results should not be lost sight of by 

 all those who may be promoting deep sinkings at any places over the 

 area which has been here indicated. 



