According to the NPS, Sheep Rock (that pointy-peaked mountain), in the Sheep Rock Unit of John Day Fossil Beds National Monument, gets its name from the bighorn sheep that once populated its slopes. At the top of Sheep Rock is the Picture Gorge Basalt. That brown line across the middle part of the mountain is the Picture Gorge Ignimbrite (pumice and volcanic tuff). This ignimbrite makes a nice marker bed by which geologists can place and date geologic events. The green soils you see in the second image are colored by the mineral celadonite. Celadonite comes from the French word for “sea green.”
And now you know.
Copyright Rebecca L. Latson, all rights reserved.