250 ACTION IN DEEP WATER. 



HILL-MAKING UNDER WATER. 



That hypothesis is not only in strict accordance 

 with the whole of nature, in all its kingdoms, and 

 in all their productions and phenomena, but it ex- 

 plains many things which otherwise are puzzles in 

 geology; and it enables even those whose means 

 and opportunities are the most limited to turn even 

 the progress of the most common labour into a 

 means of instruction and pleasure. The digging of 

 a quarry, or even the cutting of a drain, may be made 

 a study of nature, and the hand that works may 

 work with more ardour and success in consequence 

 of there being instruction, and consequently pleasure, 

 in the working. 



The coal mines, from the extent and depth to 

 which they have been worked, are perhaps the best 

 places for observing the traces of that working. 

 The coal itself has been vegetable matter, for there 

 are vegetable impressions in it. It lies generally in 

 basins, and there are in most cases many seams, 

 and some of fhem deep below others, so that the 

 " coal measures," or strata in which the coal is 

 found, have been formed gradually. They consist 

 chiefly of limestone clay, iron stone, and sandstone ; 



