6 Mr HOPKINS, ON RESEARCHES IN PHYSICAL GEOLOGY. 



TT. Secondly, we may have the intersection of two vertical veins, 

 the planes of which are inclined to each other at any given angle. 

 In such case it frequently happens, that while the continuity of 

 one vein is preserved that of the other is broken, apparently by a 

 relative displacement of the portions on opposite sides of the unbroken 

 vein. This kind of displacement is exhibited in the annexed figures, 

 which represent horizontal sections. 



p. Thirdly, we may have the intersection of veins the planes of 

 which are inclined, but at different angles, to a vertical plane. If such 

 veins be near enough to each other, their intersection will take place 

 sufficiently near the surface to be within the limits of observation, and 

 if they meet the horizontal surface in parallel lines their line of inter- 

 section will be horizontal. If the subjoined figures represent vertical 



sections perpendicular to this line, the displacements observed will be 

 such as they exhibit. 



These phenomena of faults, and mineral veins, are those which appear 

 to approximate the most distinctly to well defined laws, and therefore 

 afford the best means of testing the truth of any theory of elevation. 

 The following phenomena also bear equally on the investigations con- 



