GIESECKfe ON THE MINERALOGY OF DISKO. 341 



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-porphyry 

 and porphyry-slate. 



19. Ferruginous Clay, of a reddish-brown colour, the " Eisen- 

 thon " of Werner. 



20. Bolus, in small veins. 



21. Bituminous Wood, very rarely in minute beds in wacke 

 and basalt. 



22. Brown-coal. 



23. Pitch-coal, above described. 



The Primitive Kocks, which constitute some small islands on 

 the south side of Disko, are very rarely accompanied with any of 

 the simple minerals. The felspar of the granite sometimes 

 becomes opalescent; the granite contains occasionally compact 

 and prismatic epidote, also diallage and tourmaline ; at Kangek it 

 sometimes, but very rarely, contains some cubes of pyrites ; and 

 in one place I observed magnetic iron [ore ?], in nodules, mixed 

 with it. In the islet of Fortune Bay, I noticed some specks of 

 the green oxide of copper in the micaceous schistus. 



XLIV. — On the Cryolite^ of West Greenland ; a 

 Fragment of a Journal by SiR Charles Giesecke. 

 (RepriQted from the Edinburgh Philosophical Journal, 

 vol. vi., 1821-22, pp. 141-4.) 



Towards the end of September 1806, on returning from my 

 mineralogical excursions around Cape Farewell and part of the 

 eastern coast of Greenland, I was informed by one of the Green- 

 landers who accompanied me, that they sometimes found loose 

 pieces of " lead " {Akertlok of the natives) in a frith to the north- 

 ward of Cape Desolation (Nunarsoit of the Greenlanders), but he 

 could not tell me the exact spot. Though the unfuvourable season 

 was already advanced so far, and the equinoctial gales had begun 

 blowing so violently as to make it unadvisable to venture such a 

 doubtful excursion, yet I resolved to go in search of the place, as 

 we were near to the mouth of the frith in question. The name 

 of the frith is Arksut (Engl., the Leeward) : it was divided into 

 two arms ; that on the right of the entrance had a south-easterly, 

 and that on the left an easterly direction. I steered up the eastern 

 arm about 16 miles, and put on shore at diiferent places. I 

 already began to despair of finding lead, when I observed, at 

 some distance, but near the shore, a snow-white spot. At first 



* I know no name in the s^^stem of mineralogy more expressive of the 

 external character and the fusibility of this substance than that adopted by 

 my deceased friend Dr. Abilgaard, late Professor in the University of Copen- 

 hagen, who was the first who noticed and analysed this substance. 



