POSITION. 



able when their general planes are parallel, whatever may be 

 their dip, as in the following figure, where both the upper, 

 horizontal strata, a, and the lower, inclined series, b, are 

 conformable to each other. 



FIG. 83. 



UNCOKFOBMABLE POSITION. When a series of upper 

 strata rest on a lower formation, without any conformity to 

 the position of the latter, they bespeak a more modern series, 

 showing that the newest of the underlying group must have 

 been deposited before the oldest of the latter. They are 

 therefore said to occupy an unconformable position, as in 

 the same figure 83, where the upper, horizontal beds, a, are 

 unconformable to the lower, inclined deposits, 5. 



Occasionally the upper series is also raised, proving that 

 the lower strata have been twice lifted; first, when they 

 were themselves borne upwards; and, secondly, when the 

 upper beds underwent a like elevation. 



Various writers have cautioned the observer against cer- 

 tain deceptive appearances of the strata in particular lines 

 of coast, where beds, apparently horizontal, dip, in reality, at 

 a very considerable angle. The following figure exhibits a 

 headland seen from the south, in which the strata appear 

 to the eye perfectly level. 



FIG. 81 



