105 



When strata become horizontal, it is plain 

 that the term direction is no longer applicable. It 

 is also proportionably difficult to determine as the 

 angles of inclination are small ; and becomes 

 therefore a far less useful circumstance in tracing 

 the connections of distant strata. 



The inclination of any stratum is subject to 

 change along the imaginary line of its direction, 

 in consequence of undulations or flexures ; and 

 hence the same stratum frequently presents differ- 

 ent angles of dip in different parts. 



The direction of a stratum is also subject to 

 apparent, or local variations, in consequence of 

 flexures or undulations in an order the reverse of 

 the former ; and hence the same stratum occa- 

 sionally presents, in different places, different, ten- 

 dencies of the elevated edges. A mean direction 

 may be deduced in such cases ; but, strictly speak- 

 ing, the term is no longer applicable. 



It is lastly evident, that, in cases of compli- 

 cated curvature, nothing satisfactory can be de- 

 termined with regard either to the dip or direc- 

 tion of strata. 



