Although already 10 km long when it enters Duffey Lake, a long lake which is the focus of its upper basin, at the lake's outflow it begins a rapid descent, carving deeply between the Cayoosh Range and the main Lillooet Ranges to the south. Duffey Lake is named for Sapper Duffy, a Lieut. Patrick Duffey (or Duffy) or the Royal Engineers, who was assigned to investigate the route of the Cayoosh valley as a possible wagon road from the head of Lillooet Lake to Lillooet, which because of the steep descent westwards from Cayoosh Pass was not gone forward with. The creek's final descent to the confluence with the Seton is a deeper and deeper canyon, narrow and twisting, with the last ridges of the Cayoosh Range forming a rock wall thousands of feet in height, immediately opposite the highway across a very narrow gorge below. The north wall of the canyon was the location of the Golden Cache Mine, which started a small regional rush in 1897-1901 and whose former mill buildings were in the depths of the canyon below the highway and whose workings were reached by ramparts beneath overhangs on the highest part of the canyon wall. Opposite it was the Ample Mine, also a gold mine in the same period. This stretch of the canyon was the site of the hunt for First World War hero-turned-outlaw Frank Gott, who is commemorated by Gott Peak which is on the southern rim of the Cayoosh basin, on the divide separating it from the basin of the Stein River, which parallels it roughly to the south, and which is which is one of Cayoosh Creek's several large southern tributaries.