Complex sentence: Here it forms the boundary between Cumbria and North Yorkshire-and two other great rivers arise in the same peat bogs within a kilometer of each other: the river Swale and river Ure.
Split into simpler sentences: Here it forms the boundary between the counties of Cumbria and North Yorkshire. Two other great rivers arise in the same peat bogs here, within a kilometer of each other: the river Swale and river Ure.