262 
ERRATIC BOULDERS 
CHAP. 
June, and in a latitude corresponding with that of the Lake of 
Geneva! 
In Europe, the most southern glacier which comes down to 
the sea is met with, according to Von Buch, on the coast of 
Norway, in lat. 67°. Now this is more than 20° of latitude, 
or 1230 miles, nearer the pole than the Laguna de San Rafael. 
The position of the glaciers at this place and in the Gulf of 
Penas may be put even in a more striking point of view, for 
they descend to the sea-coast, within 7^° of latitude, or 450 
miles, of a harbour, where three species of Oliva, a Voluta, and 
a Terebra, are the commonest shells, within less than 9 0 from 
where palms grow, within 4^-° of a region where the jaguar 
and puma range over the plains, less than 2 JR from arborescent 
grasses, and (looking to the westward in the same hemisphere) 
less than 2° from orchideous parasites, and within a single 
degree of tree-ferns ! 
These facts are of high geological interest with respect to 
the climate of the northern hemisphere, at the period when 
boulders were transported. I will not here detail how simply 
the theory of icebergs being charged with fragments of rock 
explains the origin and position of the gigantic boulders of 
eastern Tierra del PTiego, on the high plain of Santa Cruz, and 
on the island of Chiloe. In Tierra del Fuego the greater 
number of boulders lie on the lines of old sea-channels, now 
converted into dry valleys by the elevation of the land. They 
are associated with a great unstratified formation of mud and 
sand, containing rounded and angular fragments of all sizes, 
which has originated 1 in the repeated ploughing up of the 
sea-bottom by the stranding of icebergs, and by the matter 
transported on them. Few geologists now doubt that those 
erratic boulders which lie near lofty mountains have been 
pushed forward by the glaciers themselves, and that those 
distant from mountains, and embedded in subaqueous deposits, 
have been conveyed thither either on icebergs, or frozen in 
coast-ice. The connection between the transportal of boulders 
and the presence of ice in some form, is strikingly shown by 
their geographical distribution over the earth. In South 
America they are not found farther than 48° of latitude, 
measured from the southern pole ; in North America it appears 
1 Geological Transactions, vol. vi. p. 415. 
