“BROWN ISLAND.”— THE DAILEY ISLANDS. 
15 
black hornblende-olivine-basalt (311), which occurs as a boss on the summit. One or 
two crateriform depressions occur on the lower portions of the island, and there seems 
little doubt that the whole island consists of volcanic rock. 
“ Brown Island.” 
This mass of land, about 15 miles long and 5 miles broad, is only apparently 
an island, for it is connected by a narrow isthmus about 8 miles long to Mount 
Discovery, a volcanic cone on the edge of the mainland. As the peninsula is so 
nearly isolated, and bears so gi’eat a resemblance to the other islands, it is convenient 
to include it in this chapter. When the ice was at a maximum “ Brown Island ” was 
certainly cut off from the mainland, which lies to the west. If the moraines covering 
the isthmus could be removed it is probable that even now an island would be 
produced. 
“ Brown Island” is 2812 feet high and entirely composed of volcanic rocks. The 
northern end is comparatively low and flat. Since many patches of rock of a bright- 
red colour occur scattered over it, we may presume that scoria-cones are present. 
The southern and higher end consists of a single crateriform hill, and around the 
crater are red vesicular basalt-lavas (605) which have flowed over the sides of the 
rim. A hornblende-basalt (608, see p. 104) occurs on the east side at a height of about 
2000 feet. This rock dips north at an angle of 63°, and from the fact that it ends 
abruptly as a cliff there is little doubt that much of the original lava-stream has been 
removed. On the north side of the crater a subsidiary peak of banded yellow rock 
forms a massive hill 500 feet high. The crater is at least half a mile in diameter, 
and a small shallow pool about 100 yards long occupies its centre. There is little 
ice or snow in the crater, the lip of which is about 100 feet above the pond. On 
the west side a white trachytic rock (606) has forced its way through the covering 
of basalt-glass, and was found on the crater-lip. On the lower slopes no rock in situ 
was observed, but the whole surface was covered with black smooth loose fragments 
of basalt (603), like the black pebbles at (Jape Crozier described on p. 11. 
The Dailey Islands. 
A number of conical islands, the Dailey Islands, rise through the floating ice 
at the head of McMurdo Sound. They are five in number, and all lie almost on the 
same east-and-west line. Four of these are small and conical, and not more than a 
quarter of a mile in diameter. The fifth is perhaps a mile long, half a mile wide, and 
200 feet high ; it is the only one that is at all easily accessible. It is situated 
on the western margin of the pinnacled ice* (Fig- 44, p. 79). The specimens 
collected are all of basaltic rocks of limburgite type (510), but plutonic boulders 
* Ferrar, Geog. Journ., April 1905, vol. xxv, plate, p. 374. 
