ABSTRACT
Streams are the arteries of Earth, beginning in capillary creeks, brooks, and rivulets. No matter the source, they move in only one direction-downhill, as the heavy hand of gravity tugs and drags the stream toward the sea. During its inexorable flow downward, now and then there is an abrupt change in geology. Boulders are mowed down by “slumping” (gravity) from their “in place” points high up on canyon walls.
