^li. 



-^Xv 



u. 



tlie 



1 



ua 



^oultl 



[ 



Sea 



ess 



^M in 

 -^tivelv • 



^^11 com' 



»-^ 



) 



"lisider 



) 



a furtietli 

 ^'ite that 

 y to tlie 

 compute 

 ms iu tlie 



uperficial 



tautlj in 

 ; volcanic 

 I craters 



oJuctS of 



■,VY 



tliose 



times iu 



a 



s, or by 

 ufer tliat 



,vas, aiul 

 mineral 



rtificiaUj 



,riiiatio" 

 f melted 



■mirse of 



,ler tba^; 

 ,erioa of 



? 



K 



Ch. XXVII.] NATURE OF SUBTERRAXEAX IGNEOUS ROCKS. 



y 



/ 



9 



organic remains 



lava currents. We may also expect tliat tlie rocks in 

 question will often be rent by eartliquakes, since these are 

 common in volcanic 'regions; and tlie fissures will be often 

 injected witli similar matter, so tliat dikes of crystalline 

 rock Avill traverse masses of similar composition. It is also 

 clear, tliat no organic remains can be included in sucli 

 masses, as also that these deep-seated igneous formations 

 considered in mass must underlie all the strata containing 



because the heat proceeds from below up- 

 wards, and the intensity required to reduce the mineral in- 

 gredients to a fluid state must destroy all organic bodies in 

 rocks included in the midst of them. 



If by a continued series of elevatory movements, such 

 masses shall hereafter be brought up to the surface, in the 

 same manner as sedimentary marine strata have, in the 

 course of ages, been upheaved to the summit of the loftiest 

 mountains, it is not difficult to foresee what perplexing pro- 

 blems may be presented to the geologist. He may then, 

 perhaps, study in some mountain-chain the very rocks pro- 

 duced at the depth of several miles beneath the Andes, Ice- 

 land, or Java, in the time of Leibnitz, and draw from them 

 the same conclusion which that philosopher derived from 

 certain igneous products of high antiquity ; for he conceived 

 our globe to have been, for an indefinite period, in the state of 

 a comet, without an ocean, and uninhabitable alike by aquatic 

 or terrestrial animals. 



Its fi-^"^ 

 coii' 



:rs 



L 



te 



ill 



to 



u 



111 



all)' 



