578 CONGLOMERATE ROCKS. 



SYNOPSIS OF THE CONGLOMERATE 

 ROCKS. 



FIRST DIVISION. 



Consisting of fragments of one rock, either 

 imbedded in a continuous base of the same sub- 

 stance, or reunited chiefly by minuter fragments, 

 or united by veins of carbonat of lime or of 

 quartz. 



A. Consisting of limestone alone: local. 



a. With angular fragments. 



This variety is found both among the primary 

 and secondary rocks. It includes the ornamental 

 breccia marbles, and is local, and attached to 

 some simple limestone. The union is chiefly 

 effected by carbonat of lime. 



b. With rounded fragments. 



This does not often occur in extensive strata 

 or masses, and is not attached like the former : 

 it is formed of transported materials. These 

 may be either primary or secondary. In the 

 latter, the progress of consolidation can some- 

 times be traced. 



