The porous Navajo Sandstone permits water to flow from the top of the plateau through the rock; but when the water reaches the less permeable Kayenta Formation, (which the water cannot pass through), the water is forced to move horizontally, appearing along the canyon walls as springs and seeps. This area is known as the Zion “spring line,” revealed by the profusion of green hanging gardens. Ýview The hanging gardens are composed of algae and moss, along with maidenhair ferns, and flowers like Golden columbine.The flowers attract birds, including Black-chinned hummingbirds and the American Dipper, who nests in the rocky outcrops among the camouflage of the hanging flowers.This bird can be observed standing on the rocks in the river and diving underwater to feed.    20 220 2 84