| Sandstones and volcanic tuffs of the Middle Miocene Ricardo Group (roughly 10 million years old) are wonderfully exposed in Hagen Canyon. Blackish rubble at top of image derives from the remnants of a volcanic basalt flow during Miocene times. |
| Sandstones and volcanic tuffs of the Middle Miocene Ricardo Group (roughly 10 million years old) are wonderfully exposed in Hagen Canyon. Blackish rubble at top of image derives from the remnants of a volcanic basalt flow during Miocene times. |