OF DISKO ISLAND. 265 



To" the north of Kakarsoaki in the colony of Upernavik, in 

 Lat. 72" 32', the floetz-trap again disappears, and granite, al- 

 ternating with gneiss, present themselves, and continue to 

 > • Lat. 73° 32', at the islands of Udjordlersoak and Tessiursak. 

 ^^ * Near Cape Nullok, in Sanderson's Hope, the floetz-trap again 

 ^^* appears in large masses of columnar basalt, resting on gneiss ; 

 ^■•rr but beyond this place, there is no farther approach, the coun- 

 ^^^ ^^try being covered by the Great Boreal Glacier, — the Northern 



Ice'ilink. > , 



The direction .of the trap-rocks, which are here spread over 

 such an extent, of country, is almost entirely similar, being 

 nearly horizontal, stretching from south-west to north-east. 

 The beds of which they are composed are of a very unequal ..^ 



^ 'i^ thickness; those of basalt are most prevalent. The hills com- 

 posed of gneiss and granite are never highly elevated ; and the 

 flcetz rocks are placed immediately on the gneiss, which is al- 

 i_^_ ways slightly decomposed upon the surface, where in contact 

 HEv ' with the trap. The prismatic basalt of this district, is of that 

 ^■JfW* species distinguished in Germany by the name of Basaltic 

 ^K^ Greenstone, ( Chrunsteinartiger Basalt). It is almost pure, but 

 ^B> sometimes contains a few detached specks, perhaps crystals of 

 ^■^ felspar. I found only in one place some small grains of augite 

 ^P and of hornblende. The massive basalt, on the contrary, often 



*• becomes amygdaloidal, by the small globules of mesotype, stil- . ' 



■; bite and quartz which it contains. It occurs very generally 



undermost, and touching the primitive rocks, which is very 

 rarely the case with the columnar basalt. 



The Trap-tufF, which is very common among the flcetz rocks .4, . ,, 

 of Disko, rests also always immediately on the primitive rocks : 

 Indeed, I never found it in any other situation in that island. 

 It appears to me here necessary to mark two varieties of 

 this rock, namely, that which consists almost entirely of frag- 

 ' ■ \. L 1 2 - ments 



