(HAITI , 



mi t M .Of GEoi KB 



I.TS 



WE have been dealing hitherto only wilh such varia- 

 strata as may arise from the form 



of the ground, from variations in the thickness of beds 

 or from < hanges in the direction and angle of dip. But 

 the outc -rop IN ly across, and 



removed entirely out of sight, by those dislocations in 

 the earth's en: : "faults 



been given by geologists. These lines of fracture gene- 

 rally form few or no features at the surface, so thai their 

 existence would commonly not be suspected. They 

 comparatively rarely appear in visible sections, but are 

 .t her to conceal themselves under surface accumu- 

 . ju>t at those points in a ravine or other natural 

 section where we mii;ht hope to catch them. Yet they 

 undoubted tute one of the most important parts 



of the geological structure of a district or country, and 

 should consequently be traced with the greatest en: 



The learner may, perhaps, hesitate to believe that a 

 geologist can satlst. -.i<e a line of fracture which 



he never actually sees. Hut a little attention to this pan 



