ISLAND OF DISKO. 271 



type. Notwithstanding, in Faroe and Iceland it is 

 found in wacke. This substance forms an opaque 

 jelly in nitric acid, frothing up and exfoliating. The 

 apophyllite also occurs in a radiated form, similar to 

 stilbite, but with a more brilliant lustre, and pre- 

 senting on the surface a crystallisation similar to the 

 cock's-comb barytes. 



8. Carbonate of Lime occurs in all the rocks of this formation, 



in cavities and veins, of a greyish- white colour, some- 

 times massive, sometimes crystallised in rhombs, also 

 in pyramids of three and six planes, and in prisms of six 

 planes. I have found it also crystallised in nearly perfect 

 cubes. 



9. Igloite, the Arragonite of Hauy, and Hard Calcareous-spar 



of BouRNON, occurs fibrous, radiated, and crystallised in 

 pyramids of three planes ; also in curvilinear prisms of 

 six planes, terminating by degrees in pyramids. 



10. Radiated and concentric globular mineral, of a yellowish- 



green colour, which I take to be Wavellite. 



11. Compact Quartz, bacUlaire, and crystallised in prisms, in 



geodes. 



12. Calcedony, massive, and very rarely in cubes. Quartz 



and calcedony occur in all the rocks. 



13. Opal, cominon, in veins and cavities, white and yellow, 



particularly in basalt. 



14. Cereolite, a mineral of a yellowish, brownish, and greenish 



colour, very similar to compact lithomarge. 



15. Green Earth, lining cavities, and sometimes filling geodes. 



16. Heliotrope, in geodes and veins in basalt. 



17. Agate in geodes in basalt. 



18. Felspar in small crystals, constituting the basaltic-por- 



phyry and porphyry-slate. 

 VOL. IX. p. II. Mm 19. Fer- 



