Complex sentence: South of the Jemseg, the Saint John River is surrounded by the low hills of the St. Croix Highlands-another component of the Appalachian range and it is joined by several lateral bays, including Belleisle Bay; then the Nerepis River and the Kennebecasis River.
Split into simpler sentences: South of the Jemseg, the Saint John River is surrounded by the low hills of the St. Croix Highlands, another component of the Appalachian range. It is joined by several lateral bays, including Belleisle Bay, the Nerepis River and the Kennebecasis River.