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Rock Climbing Photo: Up-turned grinding stone. This boulder was dislodg...
Id# 105938940, 332 x 480px
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By Adam Stackhouse
Mar 31, 2007
Quite clearly the biggest portable found yet!
By Coeus
From: a botched genetics experiment
Feb 10, 2011
I believe that this is the traditional beginnings of manufacturing on boulders.
By Morgan Patterson
From: CT
Jun 5, 2013
This isn't just erosion? How does one tell the difference between water formed holes like this and ones made by man?
By King Tut
From: Citrus Heights
May 16, 2017
^^^^The ones formed by Indigenous peoples are seen throughout California and are prominent in many places in Yosemite. Their number, depth and width are all consistent with grinding acorns during food preparation.

They are also (unless the boulder is moved) found on flat surfaces, often those that rarely see any water. A boulder moved by an epic flood would not remotely develop this pattern (rarely washed) nor would natural erosion produce such symmetry.

The ones behind the Ansel Adams Gallery in Yosemite Valley are particularly deep (this was a fave wintering location in the Valley due to sun exposure and acorns nearby). Ansel famously served Scotch and Sodas out of them behind his house. I've had Margaritas out of them. :)
Photo 17 of 83
Avg Score   5.0 from 4 votes
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Up-turned grinding stone. This boulder was dislodged and turned to a vertical position during the flood of 1996.
It's along the Merced River in El Portal.
Photo by Blitzo.

Submitted By: Blitzo on Mar 31, 2007
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