446 DOMAIN V. CALCAREOUS. 



rnarkable intermixture of compact limestone 

 with granular, escaped this great observer*. 



The singular rock which contains pholades, 

 or sea-dates, is a blackish argillaceous limestone, 

 rather of a soft consistence f. 



Primitive. That granular limestone is primitive has been 

 long allowed. Among many other remarkable 

 mountains of this stone, the stupendous heights 

 of Finster Aar Horn, Yungfrau Horn, and 

 Shreck Horn, or the Peak of Horror, in Swisses 

 land, deserve especial commemoration. Saus- 

 sure has long since observed, that it often pre- 

 sents lofty spires, like granite; and being a 

 manifest deposition, must evince that granite 

 is so likewise, It appears between layers of 

 mica slate and gneiss, as schistose siderite; and 

 alternates with common slate. Primitive lime- 

 stone is commonly white, dark iron grey, or red- 

 dish brown, and is not always granular, being 

 sometimes compact. It sometimes supplies the 

 place of quartz in mica slate, and sometimes of 

 felspar in granitoid, and a rock of the gneiss 



* Sauss. 2226. 



t Id. J356. On the coast of Aunis, near Rochelle, little oysters 

 called gryphites are forced into the mud by the sea. The whole 

 ^oon becomes a hard stone, and is called the shell-stone of Aunis. 

 Mem. Acad. de Rochelle, tome iii. 



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