Using relative dating principles and the position of
layers within rock, it is possible to reconstruct the
sequence of geologic events that have occurred at a
site. In the image below, cliffs along the Snake River
show signs of volcanic activity and deposition. The
thick, dark, gray layer at the bottom is made of basalt.
Red-colored layers are sandstone.
the cliffs in the photograph below. Try to visualize
the processes responsible for forming them. Click the
photograph to see an animation showing how the layers
may have formed.