the rapids of a river between the steep, rocky walls of a narrow canyon
See dalles in American Heritage Dictionary 4
(dălz)
plural noun
The rapids of a river that runs between the steep precipices of a gorge or narrow valley.
(dălz), The
A city of northern Oregon on the Columbia River east of Portland. An important stop on the Oregon Trail in the 1800s, it is now a busy inland port. Population: 12,100.