'Grossinger recounted the history of the creation of the bay as the sea level rose over the past several thousand years and covered what used to be a valley between the East Bay and the Peninsula. Marris marveled: "That means there is no pre-human bay." Indeed, people have lived by and shaped the bay's nature as long as it has existed.'

Read more:

Science writer Emma Marris with SFEI staff photos by Matthew Sumner, special to the SF Chronicle