The materials, also, which may be examined with ease through the wonderfully transparent water, are exactly the same as that composing the moraine, viz: earth, pebbles, and bowlders of all sizes, some of them of enormous dimensions.

It seems almost certain that _the margin of the great Lake Valley glacier, and of the Lake itself when this glacier had melted and the tributaries first began to run into the Lake, was the series of rocky points at the head of the three little lakes, about three or four miles back from the present margin of the main Lake; and that all lakeward from these points has been filled in and made land by the action of the three glaciers described_.

At that time Rubicon Point was a rocky promontory, projecting far into the Lake, beyond which was another wide bay, which has been similarly filled in by debris brought down by glaciers north of this point.

The long moraines of these glaciers are plainly visible from the Lake surface; but I have not examined them.

Thus, all the land, for three or four miles back from the Lake-margin, both north and south of Rubicon Point, is composed of _confluent glacial deltas_, and on these deltas the moraine ridges are the _natural levees_ of these ice-streams.
_e.