" we ought to meet with the same kinds 

 of earths, stones and minerals, appearing 

 at the surface in long narrow slips, and 

 lying parallel to the greatest rise of any 

 long ridges of mountains ; and so in fact 

 we find them." He remarks that in Great 

 Britain, the main trend of the outcrops 

 runs nearly north by east and south by 

 west. He notes also that in the course of 

 the earth-movements to which the terres- 

 trial crust is subject, the strata have not 

 escaped rupture. " The whole set of 

 strata on one side of a cleft are sunk down 

 below the level of the corresponding 

 strata on the other side," and he saga- 

 ciously adds that, " if in some cases this 

 difference in the level of the strata on the 

 different sides of the cleft should be very 

 considerable, it may have a great effect 

 in producing some of the singularities of 

 particular earthquakes" (Arts. 44, 50). 



It should be remembered that all the 

 geological observations by John Michell 

 referred to in the foregoing pages were 

 44 



