938 The American Naturalist. [November 
General Notes. 
GEOLOGY AND PALEONTOLOGY. 
The Glacial Catastrophe in Savoy.—The torrent of ice and 
water which caused such a lamentable loss of life at the baths of St. 
Gervais in July last was so extraordinary that M. Vallot, Director of 
the new Mont Blanc Observatory, determined to explore the region 
from which the avalanche descended with a view to discovering the 
cause and to prevent the recurrence of so horrible a catastrophe. In 
company with M. Ritter and two guides he ascended the mountain to 
the base of the Aiguille du Goûter. Here they found an apparently 
insignificant glacier, the Téte Rousse, which proved to be the source 
of the outbreak. This glacier forms a plateau nearly horizontal. It 
advances over an inclination of 40° between two converging ridges 
into a basin which has for an outlet a narrow rocky ravine. The front 
of the glacier has been torn away, exposing an enormous arched cav- 
ity, filled recently with ice. This cavern communicates by a narrow 
passage strewn with blocks of ice, with a sort of crater 270 feet long 
and 133 feet deep, having perpendicular walls of polished transparent 
‘ice, an indication of prolonged contact with water. 
It is the opinion of M. Vallot that a lake had been formed at the 
bottom of the glacier and crater. This water had undermined the ice 
crust over the upper cavity. When the ice crust collapsed the tre- 
mendous pressure transmitted to the lower grotto caused the rupture 
in the anterior part of the glacier. This explains the enormous quan- 
tity of water precipitated at once into the valley, carrying with it the 
soil of the banks, forming a torrent of liquid mud mixed with ice- 
blocks and rocks. 
It is estimated that 100,000 cubic metres of water and 90,000 of ice . 
issued from the glacier. It is possible the sub-glacial lake may 
re-form, and in view of the possibility M. Vallot advises blasting the 
rocky bottom to provide an escape for the water. 
The Iron Ores of the Lake Superior Region.—Mr. C. R. 
Van Hise has brought together under this title all the more important 
conclusions upon the subject which have been reached in recent years 
by the Lake Superior Division of the U. S. Geol. Survey. 
