JOINTED STRUCTURE. 
307 
In many places, it is evident that there lias been but little change during long periods; for 
large trees are found growing in the fissures, and others upon the separated blocks, extending 
their roots down the sides of these and into the soil below. Such appearances are observable 
in the banks of deep ravines, where there is conclusive evidence that large streams of water 
have flowed at some former period. 
Jointed Structure of the Conglomerate. 
This structure in the conglomerate usually divides the blocks into more rectangular forms 
than the rocks below. In the outliers of this rock which appear in the southern counties, the 
whole mass often appears in isolated blocks, as can be seen in the illustration under the 
description of that rock. The following sketch also illustrates the same. In the corner of 
the block, on the left, it will be seen that a portion has been removed by the intersection of 
two planes, which did not extend entirely to the surface. 
