V * *« 



OF DISKO ISLAND. . 267 





usually forms the summits of these hills, by another seam of 

 the same ferruginous substance, of a brownish colour. 



The mountain called Ounartorsak, near Godhavn, presents 

 the following proportions in one of its precipices: (See Plate 

 XVI.) 



Basalt, in columns of from three to seven sides, with some 



crystals of felspar. 

 Reddish-brown ferruginous clay. 



Amorphous basalt, with geodes of radiated mesotype. 



Reddish-brown ferruginous clay. 



Reddish-brown wacke, containing stilbite, mesotype, &c. 



The last with apophyllite, &c. 

 Granite, with gneiss. 



.%«. 



I. 



2. 



4. - 

 5. 



6. 



Basalt, 

 columnar. 





Basalt, 

 amorphous. 









Amygdaloid. 



f » 



Trap-Tuff. 



Basalt-Tuff. 





7. 



• 



■v^v% *■*• V^ V^ 



All the basalt of Disko is magnetic. That found in the 

 most elevated situations is most so; the fallen masses dispersed 

 around the base of the mountains having more power over the 

 needle than the others. 



The mountains of Disko are almost all flat at the top, and at a 

 distance present the appearance of large houses. It was only in 

 the Waygat, and in the Bay of St James, (Omenak's Fiord), 

 where I observed pyramidal and conical summits. Mannik, a 

 **$ mountain in Waygat, (see Plate XVII. ), is terminated by an im- 

 mense basaltic pyramid of four sides. On the summits of all the 

 mountains which I ascended, I found numerous rolled masses 

 of primitive rocks, often of considerable size, and of a weight 

 beyond my power to move. These masses consisted either of 

 granite, gneiss, mica-slate, siliceous-schist, quartz, or hornstone. 

 Porphyry-slate is the rarest rock among those of the trap-for- 

 mation in Greenland. Although I ascended several of the 

 mountains, I found it only in two, Unknown Island and Hare 

 Island, to the north of Disko ', and there it occupied only the 



summit. 





