San Francisco Bay formed at the end of the ice age when the series of valleys and canyons through which the Sacramento River flowed flooded.
(San Francisco Bay; formed; T:at the end of the ice age; when the series of valleys and canyons through which the Sacramento River flowed flooded) (the Sacramento River; flowed flooded; )
San Francisco Bay the Sacramento River
formed flowed flooded
T:at the end of the ice age when the series of valleys and canyons through which the Sacramento River flowed flooded