As glaciers carved the land, they formed U-shaped valleys such as Somes Sound (on Mount Desert Island), which ultimately filled with seawater after the glaciers receded.
(glaciers; carved; the land) (they; formed; U-shaped valleys such as Somes Sound (on Mount Desert Island; T:As glaciers carved the land) (Somes Sound (on Mount Desert Island; filled; with seawater; T:after the glaciers receded; T:ultimately) (the glaciers; receded; )
glaciers they Somes Sound (on Mount Desert Island the glaciers
carved formed filled receded
the land
U-shaped valleys such as Somes Sound (on Mount Desert Island T:As glaciers carved the land
with seawater T:after the glaciers receded T:ultimately