GEOLOGY. 19 



After this brief description of the primary rocks, it only 

 remains to be noticed, in connexion vdth the adopted theory 

 of their formation, that in proportion to their relative distances 

 from the fundamental granite, the greater is the comminution 

 of their particles, and the less crystalline their structure. 

 Assuming the igneous origin of granite, it necessarily follows 

 that its surface, penetrating the waters of the primitive seas, 

 would be subject to the disintegrating influence of atmospheric, 

 aqueous, and chemical agencies. The waters themselves, 

 especially when resting in the newly-formed hollows, must 

 have been heated to a high degree, the air loaded with 

 vapours, and the superficies of the earth raised to a corre- 

 sponding temperature. The process of disintegration would 

 consequently be much accelerated. The runnels and streams 

 would carry down the loose particles, disposing the heavier 

 portions first and nearest, and bearing the lighter and smaller 

 to deeper basins. Hence there exists the greatest affinity 

 betwixt these rocks, where, according to the law of their 

 aggregation, the granite is sometimes fused into the gneiss, 

 the gneiss into the mica-schist, and the quartz rock, marble, 

 and other beds all welded into each other ; and thus strongly 

 warranting the inference, that the whole series have been 

 exposed to the action of heat after the deposition and arrange- 

 ment of their component parts. 



Heat alone, of all known causes, could produce such results. 

 Added to the phenomena of veins — in the changes, dislocation, 

 and induration invariably produced upon the strata through 

 which they pass — there are few dogmas of science that can 

 boast of resting upon a wider induction of facts, than that the 

 mountains of the earth owe their elevation to the expansive 

 force of internal fire, and that its massive foundations have been 

 consolidated through the instrumentality of the same agent. 



The rudiments of all the rocks and after-formations are 

 thus re-compounded only from the waste and debris of the 

 originally sohd parts, or have been cast out from beneath by the 



