More Pictures

The two pictures below are of the Twin Sisters. Although they look similar, particularly in the second picture, the Sister on the left is 2.5 billion years old, while the Sister on the right is a mere 25 million years old. The older Sister is made of rock in a formation that geologists call the Green River Complex and is some of the oldest rock in the Lower 48. The youngest Sister is made of rock in a far younger formation that geologists call the Almo Pluton.






Oregon Trail ruts: