Sea level has risen and fallen many times in the past few hundred thousand years. Evidence of these changes are visible all around the San Diego area. Near the coast, raised marine terraces and abandoned cliffs mark these ancient shores. These are most visible in the La Jolla area, where at least three different terraces are seen along the edge of Mt Soledad.

Further inland, other evidence is visible. In the Clairemont Mesa area, there is a large north trending ridge near Convoy St which is a part of a former beach ridge. Several of these beach ridges exist in the area, some of which help define the drainage pattern in the Clairemont and Bay Ridge area.