MODERN GEOLOGY 



different strata, though the passage from one extrem- 

 ity of complete solidity to the other of complete ex- 

 pansion, in reality, must have been perfectly gradual. 

 The lowest stratum, immediately above the extreme 

 limit of expansion, will have been granite barely dis- 

 aggregated, and rendered imperfectly liquid by the 

 partial vaporization of its contained water. 



"The second stratum was granite disintegrated; 

 aqueous vapor, having been produced in such abun- 

 dance as to be enabled to rise upward, partially dis- 

 integrating the crystals of felspar and mica, and super- 

 ficially dissolving those of quartz. This mass would 

 reconsolidate into granite, though of a smaller grain 

 than the preceding rock. 



"The third stratum was so disintegrated that a 

 greater part of the mica had been carried up by the 

 escaping vapor in suspension, and that of quartz in 

 solution; the felspar crystals, with the remaining 

 quartz and mica, subsiding by their specific gravity 

 and arranging themselves in horizontal planes. 



"The consolidation of this stratum produced the 

 gneiss formation. 



"The fourth zone will have been composed of the 

 ocean of turbid and heated water, holding mica, etc., 

 in suspension, and quartz, carbonate of lime, etc., in 

 solution, and continually traversed by reciprocating 

 bodies of heated water rising from below, and of cold 

 fluid sinking from the surface, by reason of their spe- 

 cific gravities. 



"The disturbance thus occasioned will have long 

 retarded the deposition of the suspended particles. 

 But this must by degrees have taken place, the quartz 



VOL. Hi.-w 



