34 Introduction. 



basalt, etc., being too insignificant and, also, too recent 

 in extrusion upon the surface of the earth, to be of any 

 importance in accounting for the materials of either meta- 

 morphic or sedimentary rocks. 



Both in the metamorphic and sedimentary rocks there 

 is a marked discrepancy between them, in the elements 

 they contain, and those possessed by granite. For instance r 

 the proportion of lime in these rocks cannot be less than 

 15 per cent, of lime may be it is not placed too high by 

 making it even as high as 25 per cent. ; whilst in granite the 

 per-centage of lime cannot be higher than 8 per cent., but 

 5 per cent, will be much nearer the mark. 



Again, carbon is not found in granite, or in the smallest 

 amount imaginable, not as much as i in 1,000. Yet, in 

 addition to the carbon, as a hydro-carbon, in our coal beds, 

 and the carbonic acid in our atmosphere, there is at least 

 four times more carbon contained in lime, in the form of 

 carbonic acid, extending from metamorphic rock on to chalk, 

 than is to be found in all other sources put together. These 

 illustrations pertain to the positive side of the question. 



But the negative side appears to be equally decisive upon 

 the matter, for we find potash as much as 7 to 10 per cent, 

 in granite, especially in felspar, yet, in the midst of such 

 extensive disintegration, there is not so much as one single 

 stratum of potash, or any salt of it, in any portion of the 

 earth's surface, unless it be found in strata like to 

 common salt. Hence it is clear that granite never was, 



