Canyon Creek Road ascends an ancient landslide off Church Mountain that plugged the river 2,400 years ago. Rafters dodge boulders and kayakers perform tricks in hydraulics eroded out of the slide debris by the relentless action of flowing water. The resistant rocks and steep slope keeps the Nooksack River tightly contained. It cuts down into the bedrock like a hot knife and transports everything down slope. The igneous rocks change to sedimentary ones where the floodplain begins.
Sedimentary rocks are softer than volcanic ones.
The river loses its rush and drops its sediment load of boulders, rocks, and gravel as it lazily meanders across the landscape to the ocean. Salmon and trout species prefer the cold water and gravel bottoms in the floodplain. The velocity of the river water prevents fish from swimming into the upper reaches. The Pacific Ocean Plate is submerging under the continental North American Plate and creating enough heat to melt rocks. The molten rocks either erupt out of the surface in the form of volcanoes or slowly rise in the form of plutons.