CONGLOMERATE ROCKS. 686 



These are the most common, and they con- 

 sist of fragments, rounded or angular, or both, 

 united by means of clay, sand, and gravel, 

 derived from the same substances. 



A. Fragments of quartz, and of a greater or less 

 number of the primary rocks, united. 



This, under various states, forms conglome- 

 rates, attached to the sandstones, and is noticed 

 under those heads. It is either primary or secon- 

 dary, but the former contains a more limited > 

 variety of ingredients than the latter. 



B. Fragments of a greater or less number of the 

 primary rocks with limestone. 



These conglomerates appear to be connected 

 chiefly with the lowest red sandstone. 



C. Fragments of a greater or less number of the 

 primary rocks with trap. 



This conglomerate is analogous in geological 

 situation to var. A of this division, and is found 

 in those places where trap rocks exist. It forms 

 a large tract near Oban. 



D. Fragments of granite, limestone, quartz, and 

 gneiss, imbedded in micaceous schist. 



This is, geologically, the same as var. C, D, 



