 Its course is west for approx 5 miles (which brings the river to within 3 miles of the south coast at Marazion on Mount's Bay).It then flows through a steep wooded valley north of the granite high ground at Trescowe Common, formerly a mining area, before turning abruptly north near the hamlet of Relubbus.It then follows a northerly course for the remaining six miles to the estuary, passing St Erth.