Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY, 



45 



surface of the mass, the tension of it may become so far relaxed that 

 the further formation of the others shall cease. We may therefore 

 suppose it highly probable that the number of fissures formed in the 

 inferior parts of the elevated mass, will be considerably greater than 

 the number which reach the surface. 



40. The phenomena, then, to which our investigation at present 

 extends, may be represented as in the annexed diagram, a few of the 

 fissures being complete ones, or running up to the external surface of 



the mass, and the others being hiconqylele ones, or rising to different 

 heights, without reaching the surface. 



41. If we recur to what has been previously advanced respecting 

 the depths of veins, (Introd. ii. p.), we shall see the importance of the 

 fact established above, that the formation of fissures produced by the 

 causes we have supposed must necessarily begin in some lower portion, 

 and not at the upper surface of the mass, where it might perhaps at 

 first sight be supposed more probable that they would begin. 



42. We may also see, in what has been above stated, one cause of 

 the inclination or hade of a fissure. (See Introd. ii. k.) 



^. Formation of Transverse Fissures — Fissures of a Conical Elevation — 

 Modification in the Position of Longitudinal Fissures. 



43. In the case we have been considering, the whole tendency of 

 the elevatory force, acting with perfect uniformity, will be, as we 

 have before remarked, to produce longitudinal fissures ; and a vertical 



