Mk HOPKINS, ON UESEARCHES IN PHYSICAL GEOLOGY. 83 



the contiguous beds, of that enormous hydrostatic pressure, which the 

 process of injection of an extensive horizontal bed would necessarily 

 cal n.to action 1 hat the toadstone of Derbyshire is not an injected 

 bed, admits, I think of the most indubitable proof from observation; 

 and If the mterstratification of the whinsill of the north, with com- 

 parative y thin beds of limestone and shale, be as regular as it is repre- 

 sented to be, I should iiave no hesitation in coming to the s.^me 

 conclusion with respect to that bed, for the reasons ,vhich have been 

 heretofore mentioned, (Art. 77). 



In the preceding investigations, I have spoken of the law of paral- 

 lelism only as recognized in phenomena of faults, mineral veins &c 

 comprized within narrow boundaries as compared with those to ;hich 

 It has been attempted to extend it, in the theory of Elie de 

 Beaumont It is very possible, however, that the physical causes to 

 which I have referred this law, may have had a far more extensive 

 operation than that I have ventured to assign to them. The paral- 

 lelism of two mountain chains might thus be accounted for as simply 

 as that of two neighbouring anticlinal lines; but it is obvious that 

 the more i-emote they should be from each other, the less would be 

 the probability of the fissUres to which our theory would refer them 

 belonging to tlie same system, and the less satisftictory would our solu' 

 tion become. 



I have been anxious to avoid, for the present, any speculations 

 respecting the interior constitution of our globe, beyond what is com- 

 prized in the simple assumptions on which tiiese investigations iiave 

 been founded; we may, however, include in those assumptions, the 

 h)Tothesis of the elevatory forces having acted in different cases at 

 different depths. The application of our theory, alluded to in the pre 

 ceding paragraph, would perhaps require the hypothesis of these forces 

 having acted at a much greater depth in such instances, than in 

 those where the resulting phenomena are on a much smaller scale- 

 and we may observe, that if the formation of the fissures should com' 

 mence very far beneath the surface, it is extremely probable that very 

 tew would become complete fissures (see Art. 39), or would ever reach 



