yeahbut-- most of New England was covered with ice! the rivers were glacial! and there are still many deep U shaped vallies (say the Connecticut river valley!) that are glacial valleys, not just river (V shaped) valleys!

Bottom land is always valuable, and there are many places in NE were the rivers has 1 or 2 miles either side of bottom land.. really broad, U shaped valleys! but oh the hills! and the same glaciers left behind lots of rocks-- the bane of NE farmers!