Fraser River Pioneer site, page 2
Some distance (perhaps 2 or 3 km) downstream from Swanson flat is the location of the Chinese mining site. The ditch came down to here. The sluice was set up at right angles to the ditch and to the Fraser river.
Dirt was shovelled into the sluice and the rocks were pitched over it, making rows of rocks when the sluice was moved over and the next row of rocks thrown over it and so on. This resulted in an area with parallel rows of rocks, sometimes called "Chinese Walls". Below the placer area on a lower bench nearer the Fraser river was the Chinese camp. Looking down the rows of rocks, you can see a corrugated effect. Actually many of these shots were taken across the rows. Time has flattened the rows down considerably.