This site extends from the edge of the River Tees to the north end of the golf course. This stretch of beach and sand dunes at the mouth of the River Tees exists here because of the two and a half mile long breakwater which was finished in 1888. The dune system can be unstable, sometimes parts are washed away by winter storms, and so the plants that grow on the dunes often have deep roots that can regrow when snapped. At high tide the sea once entered the large ponds behind the dunes where saltmarsh plants used to grow, but now these are blocked by sand dunes and so normal pond plants are steadily colonizing. Large amounts of slag have been dumped adjacent to the breakwater on which now grows a fascinating community of plants that are normally found on limestone.