Considerations on Volcanoes, 373 



rents, and many other things ; and the waters of the ocean 

 dissolved silex, and such other minerals as water under such cir- 

 cumstances could hold in solution. And then the disintegrated 

 crystals that were suspended subsided ; the felspar and quartz first, 

 and afterwards the mica, as being more buoyant, and the pressure 

 produced a parallelism gradually increasing, and thus were formed 

 the gneiss beds. 



A period at length arrived when the force of expansion was 

 checked by the gravitating column, and thus it was stopped by 

 this pressure " from progressing further inwardly." The lowest 

 stratum was granite disaggregated, the next was granite disinte- 

 grated, reconsolidating into granite, the third became gneiss, and 

 the fourth, «one, consisting of turbid and heated water, containing 

 the other earths and minerals, formed mica and slate, carbonate 

 of lime, and so on. The fifth stratum was aeriform, and formed 

 the atmosphere. 



And then as the evaporation of the ocean went on, more pre- 

 cipitations took place, and there were formed the transition for- 

 mations : and beneath this crust a new process was commenced. 

 The outer zones of crystalline matter were refrigerated, and ab- 

 stracted caloric from the nucleus ; and by some other operations, 

 which, we grieve to say, we cannot abridge, the process of conso- 

 lidation " progressed downwards " with the increase of the ex- 

 pansive force in the lower strata, and the upper zone of crystal- 

 line matter which had intumesced was re-solidified, and the 

 gneiss formation once more was the result. And beneath this, 

 the granite was again solidified and returned again to its former 

 condition ; but the increasing expansive force overcame the re- 

 sistance, and produced fissures, and thus the inferior crystalline 

 zones came out of them in a " solid or nearly solid state," toge- 

 ther with the intumescent granite, and extravasations in the form 

 of lavas. 



And the reason why the foliated rocks protruded so easily, 

 was their peculiar structure, which allowed them to slide, while 

 the crystals also were elongated in the direction of the motion, as 

 happened in the " pearlstones " of the trachytic formation. And 

 the rapid expansion of the crystalline rock in the fissures while 

 the water was boiling, ground the crystals into powder, and pro- 

 duced M porphyries or serpentine ;" while if the " particles were 

 comminuted to an extreme degree by the friction attendant on 

 the intumescence," they may have " effected entirely new com- 

 binations," and so produced diallage rock, hornblende rock, <$*c. 

 And when the heat was not sufficiently great to boil the water, 

 the aqueous vapour exuded through the walls, bringing with it 

 silex in solution, together with other mineral and metallic matters 

 sublimed from the lower part of the fissure. 



Then all this commotion and breaking up produced the waves 



