Complex sentence: It is named after the Silver Pit, which is a name given by North Sea fishermen to a large depressed area in the bed of the North Sea, which is likeliest an old river valley made when the sea level was lower in the Ice Age.
Split into simpler sentences: It is named after the Silver Pit, which is a name given by North Sea fishermen to a large depressed area in the bed of the North Sea. The Silver Pit is likeliest an old river valley made when the sea level was lower in the Ice Age.