Complex sentence: Archaeologists have yet to unravel the mystery, and some modern Pohnpeians believe the stones were flown to the island by use of black magic; however, a short dive between the island and the quarries shows a trail of dropped stones.
Split into simpler sentences: Archaeologists have yet to unravel the mystery, and some modern Pohnpeians believe the stones were flown to the island by use of black magic. However, a short dive between the island and the quarries shows a trail of dropped stones.