NOTES ON ANTARCTIC ROCKS. 463 
In 1831 Biscoe in the brig Zula discovered Enderby’s Land. 
In 1839 Balleny discovered Balleny’s Island, a volcano 12,000 feet 
high, and adjoining it the active (?) voleano of Buckle Island. In 
1839 the important French Expedition, under Dumont D’Urville 
explored the South Shetlands.’ 
Syenite, occurring in needle-like pinnacles, was found at Smith 
Island, while this island as well as Livingstone, Greenwich, 
Roberts, King Georg? and Elephant Islands were proved to be 
of primary schistose formation, traversed by intrusive igneous 
rocks. The trend of these rocks was ascertained to be north-east 
and south-west, dipping (?) at from 29° to 30°. Powell Islands 
were discovered to belong to a somewhat similar formation, being 
composed of phyllite-like talcites and quartzose talc rocks. 
In the South Orkneys near Laurie Island the occurrence of a 
greyish-white limestone is recorded, as well as that of phyllite-like 
schists, their strike being north-north-west and south-south-east, 
and their angle of dip over 60°. 
The granites and syenites, of which the New South Orkney 
Islands consist, were found to have contributed the greater 
number of the erratics observed on the coast of Terra del Fuego. 
An interesting description is given in the above work of the 
remarkable volcanic crater, among the South Shetlands, known 
as Deception Island. The basin of the crater is submerged, the 
sea being sixty-seven feet deep at the centre of the basin, and 
the latter being about five miles in width measured at sea level : 
the maximum diameter of the crater ring measured at sea-level 
across its outer circumference is about eight miles, thus giving 
an average width of about one and a half miles for the portion of 
the crater rim above sea level. The crater is described as being 
built up of alternate layers of ice and volcanic tuff. Fumaroles 
were discovered to the number of at least one hundred and fifty, 
a... 
ws Voyage au Péle Sud et dans l’Oceanie. Sur les corvettes L’ Astrolabe 
pr ae Zélée, exécuté pendant les Années 1837-40. Géologie, Minéralogie 
phie physique du Voyage, Vols. xx11.-xxt., Paris, 1848. 
