Complex sentence: The River Thames flowed further north than it does today before converging with the ancient Bytham River, while the landscape of a large part of modern-day Norfolk and Suffolk consisted of a series of clay ridges and troughs known as the East Anglian Crag Basin.
Split into simpler sentences: The River Thames flowed further north than it does today before converging with the ancient Bytham River. The landscape of a large part of modern-day Norfolk and Suffolk consisted of a series of clay ridges and troughs known as the East Anglian Crag Basin.