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 in the repeated ploughing up of the sea-bottom by the stranding of icebergs, and by the matter transported on them.

(11/15.

"Geological Transactions" volume 6 page 415.) 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 degrees of latitude, measured from the southern pole; in North America it appears that the limit of their transportal extends to 53 1/2 degrees from the northern pole; but in Europe to not more than 40 degrees of latitude, measured from the same point.