876 THE ZOOLOGIST. 
vinced myself that in any case a good deal of the gneiss was washed 
down from the interior; therefore this torrent must either cut down 
to a formation of gneiss, or else the snow-covered uplands of Disco 
Island are strewn over with ice-transported blocks, that during the 
summer thaws work down into the stream. Our return track led 
us amidst a great number of bergs: some of these ice-islands were 
over a hundred feet above water, and as they were frequently 
“calving” we kept at a respectful distance from them. The first 
notice given of disruption was seeing the flocks of sea-gulls that 
had been resting on the iceberg rise hurriedly in the air; then a 
mass of ice slid into the sea, making a great turmoil in the waters, 
followed by a loud report. The newly exposed portion of the berg 
was at once enveloped in mist, owing to its being so much colder 
than the air with which it suddenly came in contact. If the 
detached mass of ice is of sufficient size to upset the equilibrium 
of the berg the sight is still grander: the enormous mass slowly 
moves ; the side that is rising pours from off its flanks volumes of 
water that descend in enormous cataracts of foam. This movement 
of the iceberg back and forwards is slow, but exceedingly grand ; 
the oscillations of the enormous mass continuing for half an hour 
before the berg attains its new position of poise and rest in 
the sea. 
During this excursion I noticed the following species of birds: 
—Plectrophanes lapponicus, breeding at Fortune Bay; P. nivalis, 
common, and breeding wherever we landed; a single pair of 
Corvus corax, in the cliffs of Laxebught ; Larus glaucus, common, 
also breeding in the cliffs near Laxebught, the spot being called 
“ Nargavak,” after the Greenlandic name of the bird, which word 
gives a very faithful representation of its note; ZL. leucopterus, 
common; a few pairs of Slercorarius crepidatus; Fulmarus 
glacialis, very abundant: the natives give the name of “ Igarsok” 
to the dark-coloured birds, which I was informed by Mr. Fencker, 
of Godhavn, means cook, that functionary on board the Danish 
trade-vessels usually dressing in a blue jersey, whence the 
derivation of the name. Uria grylle was very abundant: amongst 
hundreds that I saw in the vicinity of Fortune Bay was one com- 
pletely black, the white spot on the scapulars not showing. Alca 
brunnichi abundant; but A. torda scarce in comparison. Small 
flocks of Harelda glacialis were met with, and some numbers of 
Somateria mollissima, the most numerous duck being S. spectabilis; 
