MODE III. LIMESTONE. 449 



A limestone, containing large shells full of 

 sand. Sauss. 284. 



Aspect 2. Micaceous. Primitive granular lime- 

 stone is often interspersed with mica, and some- 

 times with orbicular crystals of quartz. It has 

 already been observed, that the mere mixture of 

 mica can never be understood to alter the deno- 

 mination of the stone. 



Micaceous limestone, from the Alps. 



The same, from the Grampian mountains, in 

 Scotland. 



The substance called Cipoline marble is often- 

 so coarse as rather to belong to this division. 



Limestone, with nodules of "mica and of sand, 

 from the Pyrenees. 



A micaceous limestone, in which the mica is so 

 abundant that the calcareous mixture is scarcely 

 distinguishable. Sauss. 1 8 1 J . I 



STRUCTURE II. COMPACT. 



Texture, compact, generally massive and earthy, Characters, 

 sometimes schistose. 



Hardness, from the gypsic to the marmoric. 

 Fracture, fine scaly, sometimes large and flat 

 :onchoidal, sometimes uneven. Fragments, arnor- 

 }hous, rather sharp. 



VOL. i. 2 G ' 



