Along the west bank of Z Canyon, 18 feet wide and 400 feet deep is Gardiner Cave, in Crawford State Park, a 49-acre, forested, day-use park. In the cave are stalactites and stalagmites, rimstone pools, flow stone, and other beautiful formations. Two large fluted pillars, dividing the main passageway, display all the colors of the spectrum, with violet and pink predominating. Numerous nacreous pillows rise from a few inches to several feet. In another section a curious formation resembles a frozen waterfall; over it hangs a canopy of glistening icicles of lime. Crystal formations hang like chandeliers from many points on the ceiling. Gardiner Cave is the the third longest limestone cavern in Washington. Just south of the state park is Boundary Dam, built in 1967. Owned by the City of Seattle, the dam provides 50 percent of Seattle’s power.