As the glaciers moved southward and began to retreat by virtue of the melting at their southern ends, they left behind till (rocks and soil deposited directly from a glacier), which at the terminus of the glacier formed ridges called moraines.
(the glaciers; moved; southward) (the glaciers; began; to retreat by virtue of the melting at their southern ends) (ridges; called; moraines) (they; left; behind; T:till (rocks and soil deposited directly from a glacier), which at the terminus of the glacier formed ridges) (rocks and soil; deposited directly; from a glacier)
the glaciers the glaciers ridges they rocks and soil
moved began called left deposited directly
southward
to retreat by virtue of the melting at their southern ends
moraines
behind T:till (rocks and soil deposited directly from a glacier), which at the terminus of the glacier formed ridges
from a glacier