Notice: "Cache seekers assume all risks and responsibilities involved in seeking this earthcache." “Just because it is there, doesn’t mean you have to seek the cache!” Don’t let earthcaching control you, but rather you control earthcaching.
***To access deep into this area, the Earthcachers will need a four wheel drive or park at the designated points and hike in less than a half mile.***
For several million years the Columbia River has slowly moved eastward to its current course because of the uplift of the Cascade mountain range and has created an ox bow in the river that passes what now is called White Bluff. As the river turns south from there, the mighty Columbia deposited rounded river rocks along the eastern shore at the end of the ox bow between Baxter Canyon and Parson Canyon. The stones have been piled to the height of 150 meters as the river turned, but the rock couldn’t. Where these rocks originate was anywhere up river along Columbia’s path.
In this area, the river deposited black and red basalt, granite, jasper and lots of opaque (can’t see through) white to yellow quartz. The rare find is an agate. Named after Greek Philosopher Theophrastus and the Achates River where he found them 3,000 years ago.
Columbia River Agates are rocks made of silica, chalcedony and quartz. These stones are fragments of what were left of petrified wood or Thundereggs after much river tumbling that came from eroded soil or lava beds. They may have formed as silica filled gas holes of rhyolite lava or as the silica leached in and replaced the organic matter of wood.
Agates are easily discovered for they are translucent (see through) when held up to the light and come in many colors. At this location, they are mainly amber but colors like red, purple and white are also found. Most are 1 to 2 centimeters in length. A large agate the size of 10 centimeters would be very rare but have been found. They look like laminated wood and are also translucent.
Suggestion: Search in the morning with the sun rays coming over the cliff, an agate will glisten in the light like a small shard of glass. Also, using a spray bottle filled with water to shine up the rocks may help.
Small Columbia River Agate found at the site.
Large Columbia River Agate taken from cliff face on one of my visits.
To log this earthcache: Please send me the answers to the following questions via email or the geocaching.com message center.
1. Estimate the height of the exposed river rock cliff from the road to the edge of the top soil.
2. What is the difference between quartz and an agate found at this site?
3. Why was the river rocks deposited at this location in such a large quantity?
4. Make an honest attempt to search the area for an agate. Did you find one? If so, describe.
Optional: Upload a photo to the page of any agate finds, local wildlife, unique vegetation or geology in the area.
Additional study and sources:
Video: Columbia Basin Agate Hunting: Fir Road
Columbia Basin Agates
What Are Agate, Jasper and Chalcedony?