582 CONGLOMERATE ROCKS, 



a. The argillaceous schist imbedded in the 



limestone. 

 b* A confused mass of fragments of botfe 



substances. 

 c. Fragments of limestone imbedded in 



argillaceous schist. 



These rocks belong to the primary class. 

 Some of them, as that of Sienna, are known 

 among the ornamental marbles. They accom- 

 pany limestone and schist when these approxi- 

 mate and alternate, and are found, in this country, 

 in Isla, and in the Garveloch Islands. It is unne- 

 cessary to form a title to include similar com- 

 pounds of shale and limestone, as they are in 

 every respect the same. The}' are, however, 

 rare ; and of course appertain to the secondary 

 rocks. 



C. Fragments of limestone imbedded in mica- 

 ceous schist: local. 



This variety occurs in cases where limestone 

 accompanies micaceous schist, and is found in 

 Isk. 



D. Fragments of granite with micaceous schist 

 or gneiss: local. 



