To the east of the river, both above and below the lock, is the site of Combretovium, known to have contained two Roman forts. Finds have included a bronze statuette of Nero and a saddle-cloth weight, which may indicate that cavalry was stationed there. After Shamford Lock, the river is crossed by the railway, with Blakenham Lock situated to the north of Great Blakenham. The Gipping Way reverts to the east bank at the lock, and nearby is a nineteenth-century house called Gipping Weir. The river and railway re-cross, and to the east of the river there are extensive flooded gravel workings. At the southern end of the workings, the site of Claydon lock now lies beneath the A14 dual carriageway. Continuing southwards, the next lock was Paper Mill Lock, beside which is the paper mill. To the west, but separated from the river by the railway, is Suffolk Water Park, which occupies flooded gravel workings. To the south stood the north warehouse at Fisons Horticultural Division, which was built around 1858 to manufacture superphosphate fertiliser. To the south of the building, Edward Packard established the world's first superphosphate factory between 1851 and 1854, and the two companies amalgamated soon after Joseph Fison set up his rival enterprise in 1858. Somersham Watercouse flows around the western edge of the Suffolk Water Park, and joins the west bank. The factory was closed in 2003 and completely destroyed in a fire, believed to be arson, on 6 May 2019.