511 
THE GEOLOGIST. 
Pimclibowl. Po:iidou is a cone of very liglit cinder. Leura is a broken 
crater on the edge of tlie rises, while Purrumbete is a beautifnl sheet of water, 
a fesv miles distant, which once, as a crater, discharged vast quantities of ash. 
The other principal volcanos of "Western Victoria are Biininyonp;, Blowhard, 
Xooiat, Gellibrand, Kapier, Franklin, Cavern, Shadwcll, Lower Uill, Clay, 
Elephant, Eckersley. ISo adequate impression can be formed as to the period 
of the activity of these cones and craters. Tliere is a freshness in most of 
them, indicative of a comparatively modern date, and the natives have tradi- 
tions of the eruptions of several of them. 
GLACIAL MOVEMENTS OX THE NORTH-WEST COAST OF AMERICA. 
By Su- E. Belcuei^, F.G.S. 
Sir E. Balcher said that early in September, 1837, his expedition ran down 
the coast of Korth America, between Ports Etches and ]\Iulgiavc, in order to 
fix the position and determine the heights of ^ilount St. Elias. The icebergs 
Avhich hung about the coast were much larger than those which he had seen in 
Behring's Strait, or off the mouth of the fiords in the vicinity of Port Etches. 
He believed that in Icy Bay the lower bodies of the ice were suljject to slide, 
and that the entire substratum, as frequently found vrithin the Arctic Circle, 
was composed of slipi)ery mud. In Icy Bay tlie apparently descending ice 
from the mountains to the base was in irregular broken masses, which tumbled 
in confusion. The motion was clearly continuous. As to the causes which 
operated in producing the constant displacements of the glacier, and the pro- 
lusion of the bergs seaward, many theories had been proposed. Plis impression 
was that, whatever was the intensity of cold under which congelation had 
taken place, the actual temperature due to the ice was merely that of 83 
degrees Eahrenheit, and that self-registering thermometers, proj^erly buried in 
ice or snow, subject even to the very lov.' temperature of degrees, 5 below 
zero, on the external skin, only indicated the proper temperature of freezing 
water. In the very high 'latitudes of Go degrees to 7G degrees North, the 
snovr on the surface of the snow-clad elevations furnished sufficient water to 
undermine the lower beds of snow-ice, and bore a passage to the sea. How- 
ever firm the crust might be in certain positions, a furious torrent had been at 
work beneath. Was the conclusion to be that the temperature of the earth must aid 
in keej)ing up a temperature sufficiently liigli to prevent the water hidden from 
light from congealing ? The advance of vegetation was another ])roof ; the 
ground-willow, saxifrages, and many other plants producing their shoots before 
light caused the immediate expansion and colouring of the leaf. Tiie earth's 
temperature, acting on the lower portions next to the soil, aided in facilitating 
the travel of the slip of the snow-ice of which these glaciers were composed 
to lower levels. In all ice-formations there might be noticed, at the season 
which followed the period of day-frost or preceded the spring, a peculiar dry- 
ness, the result of evaporation of the superfluous water, attended by dense 
fogs. An ominous cracking was then experienced, which had been misrepre- 
sented by some of the first xVrctic explorers as the breaking of the bolts of 
their vessels : no bolt was ever traced to have been so broken. He imagined 
Tiiat the soil on which masses of eternally -shifting ice reposed, must be, from 
never being exposed to the sun's rays, of a loose, boggy, or muddy nature, 
v. hich facilitated slipping. The uiulermining facilitated cracking, ami the very 
aciiou of alternate iVeeiiing and thawing tjetwcen the exposed surfaces, serviiio 
