SOLIDIFICATION OP SAND. 167 



lied into them during the process of deposition. If 

 we disturb any of these beds, we find shells, bones, 

 or vegetables, which will differ according to the cir- 

 cumstances under which the beds have been form- 

 ed. In the deposites of fresh-water rivers, the re- 

 mains of fresh-water animals will be found ; in those 

 of the sea, marine animals will be abundant. 



Geologists have accordingly availed themselves 

 of this important fact ; aixd when they find the re- 

 mains of terrestrial and fresh-water animals in a 

 deposite, they call it a fresh-water bed, and thus ob- 

 tain some information concerning the circumstan- 

 ces under which it was formed. 



Let us now suppose that these beds of clay and 

 of sand at the bottom of seas and of rivers are rais- 

 ed above the surface of the water, and exposed to 

 heat and pressure, in what would they differ from 

 any similar beds associated with known rocks 1 

 Is it beyond the bounds of possibility that this 

 may eventually occur, and what is now covered by 

 water may become dry ground 1 Geologists believe 

 that this has happened in the instance of all those 

 rocks whose stratified texture evinces that they 

 were at a former period produced by deposition ; 

 and it is not unphilosophical to believe, that what 

 has happened once may happen again. Indeed, it 

 is well ascertained that the new-formed strata of 

 the seas of Asia Minor consist of stone, and not of 

 loose, incoherent materials. Almost all the streams 

 and rivers, Hke many of those in Tuscany and the 

 south of Italy, hold abundance of carbonate of lime 

 in solution, which serves to bind together the sand " 

 and gravel into solid sandstones and conglomerates 



