Complex sentence: The Permian Phosphoria Formation of the western United States represents some 15 million years of sedimentation reaches a thickness of 420 metres and covers an area of 350,000 km 2.
Split into simpler sentences: The Permian Phosphoria Formation of the western United States represents some 15 million years of sedimentation. It reaches a thickness of 420 metres and covers an area of 350,000 km 2.