Complex sentence: The driftless area of Southeast Minnesota was untouched by the most recent glaciation, and because of the absence of glacial scouring and drift, presents a widespread highly-dissected aspect absent from other regions of the state.
Split into simpler sentences: The driftless area of Southeast Minnesota was untouched by the most recent glaciation. In the absence of glacial scouring and drift, this region presents a widespread highly-dissected aspect absent from other parts of the state.