Complex sentence: Following the most recent ice age, the Middle Connecticut River Valley sat at the bottom of Lake Hitchcock, and owes its lush greenery and rich, almost rockless soil to the ancient lake's sedimentary deposits.
Split into simpler sentences: Following the most recent ice age, the Middle Connecticut River Valley sat at the bottom of Lake Hitchcock. Its lush greenery and rich, almost rockless soil comes from the ancient lake's sedimentary deposits.