Mr. Warburton on Magneslan Breccia. 209 



stone with the intermedium (perhaps) of the coal measures, the 

 other abutting against the broken edges of the strata of limestone at 

 the base of its escarpment. Perhaps there may be found some valley 

 of denudation connecting together the two plains, which being itself 

 filled with red marl of the same description, there may be an unin- 

 terrupted bed of marl through the valley from one plain to the other. 

 The determining of this question would be of some importance 

 as a matter of speculation, and of some practical consequence to the 

 coal viewer. Those who consider the red marl as one of a complete 

 series of beds succeeding one another in a uniform order, will in 

 every case expect to find the coal measures on sinking through the 

 red marl. If on the contrary we suppose denudatory or other dis- 

 turbing causes to have been in action previously to the deposition of 

 the red marl, we might expect to find the red marl immediately in- 

 cumbent upon any rock from the coal measures to the granite inclu- 

 sive, just as the alluvial beds in which the bones of elephants are 

 found in consequence of previous denudation are discovered resting 

 either upon the blue clay of London, upon the Oxford oolite, or 

 any other bed : and on this view of the subject the red marl will 

 no more be an indication of coal than of any other member of the 

 lower strata. 



