64(j CoctL finding. 



enable us to judge of the probability of uniting or extending 

 our coalfields. 



For solving these important questions on our coalfields, some 

 few years since noticed by Mr. Coneybeare in a very general 

 way (not altogether correct), I think much may be deduced, 

 both from the observations of the geological phenomena, and 

 from experience. 



Some are certainly not extricable in the direction of their 

 ranges, while others appear to be so; and, therefore, there is a 

 probability of some of them being united. 



Some of the coalfields, particularly in the middle of the 

 island, seem not yet wrought to any well defined limits of the 

 coal series ; and, consequently, in such cases there is good 

 ground for expecting an extension ; and especially as geology, 

 by its settled order of superposition in the rocks, does away 

 old erroneous notions of cut-ofFs, &c, by the red rock, and 

 by the interposition of faults or dikes. 



From the numerous instances of now well-ascertained un- 

 dulations across the general ranges of the strata, by which 

 their planes are formed into caverns, and, intermediately, in 

 the reverse of these forms, so that the strata of coal may rise 

 on one side up to an unconformable covering, cut off by the 

 red marl or red rock, there may be good reason to expect the 

 coal-measures to go down again on the other side of the so- 

 called anticlinal line at no great distance ; and especially where 

 it can be ascertained that such lateral rise of the strata has not 

 brought up the deepest part of the coal series ; but, where the 

 millstone grit or mountain limestone appears, there, with cer- 

 tain exceptions, the case may be decisive. 



That there are such opposite lateral rises and dips in the 

 strata, where the coal-measures are deeply unconformably co- 

 vered by the red marl, is well known in the extensively wrought 

 collieries of Somersetshire (where I commenced my studies of 

 geology) ; and, consequently, the planes of the coal are sub- 

 ject to hollows and ridges, though the extent of these irregu- 

 larities may not yet be known. 



We see that the strata, in part, or in whole series of strata 

 in their superficial exposures, form such natural hollows and 

 ridges to a great extent, chiefly across the bearings of their 

 ranges ; and, therefore, we have a right to expect suck forms in 

 them, even where they are deeply covered. 



The broad and very long coalfield of South Wales termi- 

 nates north and south with opposite rises in the strata. 



The coal in Durham rises, in its southward boundary, nearer 

 to the surface; so that good coal is found at no great depth 

 beneath its unconformable cover of magnesian limestone. 



