132] A TOPOGRAPHICAL 



been carried off by the action of air and water. The formation of 

 coal must therefore be referred to a very remote period in the 

 history of the earth, as it must have preceded the existence of 

 mountains. The shells of marine animals seem to have furnished 

 the substance of those immense beds of lime-stone which envelope 

 the earth, raised into their present form and appearance. It 

 appears also, from the rearing of the beds of lime- stone, and their 

 broken and irregular position, that theiv present state could not 

 have been the effect of any gradual operation of nature, but of 

 some sudden and violent effort or earthquake. 



When the elastic vapour and air, that were the cause of the 

 earthquakes and elevation of strata, began to lose their force, 

 either by escape at the fractured tops, or by condensation from cold, 

 the weight of the incumbent strata would incline them to subside ; 

 and this subsidence being irregular, would occasion still greater 

 irregularities in the fractures, and be the cause of the faults, falls, 

 and slips, which now appear. Many irregular vacuities must also 

 have been left, which since have been filled up by argillaceous and 

 rocky substances, that have fallen or been washed into them, more 

 or less consolidated. 



The most singular and extensive vacuity in the coal of this 

 country, now filled up with clay and argillaceous rock, is that oc- 

 casioned by the separation of the two upper beds of the main coal, 

 called the flying reed, and which begin to part from the lower beds 

 of the coal at Bloomfield colliery, from whence they continue to di- 

 verge for several miles, till they crop-out at the surface, and are 

 lost before they arrive at Bilston. The separation of strata origi- 

 nally contiguous, and the subsequent interposition of adventitious 

 matter, is a very curious fact in the history of the earth. 



The coal does not crop-out on its approach to the Rowley-hills, 

 as it does to the Dudley lime-stone hills, but continues its course 

 some way under them. The formation of these basaltic hills seems 

 more difficult to explain than that of the lime-stone hills, for we 

 know that the latter are part of strata which extend themselves 

 horizontally over a great tract of country, but which in some places 

 are elevated from their inferior situation by some violent convulsion, 

 of which we see manifest indications, both in their own dislocated 

 state, and that of the superincumbent strata. But, with regard 

 to the stone composing Rowley -hills, we do not know of any such 

 inferior stratum, by the elevation of which these hills could have 

 been formed. If it be pretended that basaltic hills are of the kind 



