Much of the city is on a low range of hills running parallel to the coast. On average, it is around 80 metres above sea level. Sunderland is divided by the River Wear which passes through the middle of the city in a deep valley, part of which is known as the Hylton gorge. The only two road bridges connecting the north and south halves of the City are the Queen Alexandra Bridge at Pallion and the Wearmouth Bridge just to the north of the City centre. A third bridge carries the A19 trunk road over the Wear to the West of the City.