The Fraser River in northern Labrador flows west to east in geological trench. The gorge is narrow and deep. The upper watershed drains to Tasisuak Lake. Eastward the rift widens to shallow, brackish ponds where flow reverses with the flush of tide. Salt marshes border the mouth and vast sandy delta littered with bouders stretches to Nain Bay (about 35 km (22 mi) west of Nain).