48 



existed at all, it lay at enormous depth ; and this reflection 

 induces the hope that under 'many parts of the country now 

 belieyed to be barren, or in which coal is supposed to be 

 hopelessly buried beneath more recent strata, it may yet be 

 found at moderate depth. 



THE COAL MEASUKES. 



Between the secondary, formations, which we have hitherto 

 been considering, and the carboniferous strata, to which I 

 would now direct your attention, 'there are many points of 

 striking contrast, 



The former bear little evidence of disturbance, they occupy 

 a nearly horizontal position, and they are all approximately 

 conformable to each other. The latter, on the contrary, 

 exhibit every possible mark of disturbance ; they generally lie 

 at a high angle, and they are consequently not in conformity 

 with the overlying rocks. A period of great denudation 

 would appear to have succeeded the disturbances to which I 

 have referred, for the irregularities have been washed off, 

 and the new red sandstone has been deposited on a com- 

 paratively level surface. 



In treating of a formation so extensive within the limits of 

 so short a paper, it is obviously impossible to put before you 

 detail sections ; and I shall therefore confine myself to those 

 broader features which are likely to be of general interest. 



The coal measures have been separated vertically into two 

 great divisions, by the intervention of an immense mass of 

 coal measure sandstone, well known in this and other 

 districts as the Pennant rock. The upper division includes 

 all the coal-bearing strata above the Pennant, the lower 

 division takes in all the strata intervening between the Pen- 

 nant rock and the Millstone grit. 



The Upper Division embraces what are locally known as 

 the first, or Radstock, and the second, or Farringdon, series. 



