350 H. E. Eippisley — Somersetshire Coal-measures. 



measure sandstones. Frequently the lithological character is so 

 entii'ely distinct, that any one could tell the difference, say, between 

 a specimen of Millstone Grit and Pennant ; but this marked difference 

 sometimes merges into a marked resemblance, and it may often be 

 impossible to obtain organic remains to decide the question. It is 

 always to be remembered that sandstones, even if of no very great 

 thickness, are apt to claim an undue share of attention as to the 

 proportion of a district that they occupy, partly owing to their 

 hardness and the consequent difficulty or expense in working in 

 them underground, and partly from their prominence (from hardness) 

 at the surface, rendering the observer apt to neglect the greater bulk 

 of softer measures which do not show themselves in such an ob- 

 trusive manner. 



Other subjects in connexion with the correlation of the district 

 are treated of in the original of this summary, the lucidity of which, 

 it is feared, suffers somewhat by compression and by the absence of 

 the drawings showing suggested correlation of seams; amongstthem — ■ 



As to the process by which the commonly accepted theory has 

 arisen from the extremely complicated structure of a district in 

 which it is perfectly impossible to trace on the maps boundaries of 

 series or crops of strata by flowing curved dotted lines, as some- 

 times attempted. 



That some different conclusions would have been arrived at if 

 sections had always been drawn to a natural, and not to a distorted, 

 scale, which, however convenient for some purposes, is peculiarly 

 inapplicable to sections consisting largely of inclined strata. 



As to the structure in the two mile interval between New Eock and 

 Norton Down, and at Strap Pit, Downside. 



As to structure at Coal Pit Lane, Bishop's Sutton and Temple Cloud. 



Eemarks on some of the faults, with a simple explanation of the 

 cause of inequality of overlap at the Eadstock slide fault. 



But sufficient has already been written to show the general 

 direction in which inquiry into a confessedly difficult subject may 

 be carried on, and in conclusion the writer begs to thank the 

 many able men engaged in the district who have kindly afforded 

 information, rendering it possible to arrive at conclusions, which, 

 though not put forward by any means as final, or incapable of much 

 improvement by the evidence of further facts from new workings, 

 would, but for their aid, have been founded on insufficient data. 



Probably the amount of coal within reach in this district is just as 

 large, whether, though the Coal-measures may be shallower in it 

 than usually supposed, it contains chiefly only one, the lower, series 

 of measures so thrown up and down as to be within reach at almost 

 any point, or whether it consists of three unbroken basins one within 

 the other ; and it is evident that if at a colliery we have a set of 

 seams that are found to be of good quality for various purposes, it 

 makes no difference as to their suitability or value, whether they 

 belong to an upper or a lower series, though a correct notion of 

 correlation, if we can arrive at it, is of the highest importance for 

 new winnings or from a geological point of view. 



