It might be old volcanic ash. We're sitting on top of about 300 feet of the stuff. It like mineral gravy when wet, and like weak concrete when dry.
Phil Hawkins wrote:This stuff isn't rock - it's just really hard packed ... something. It crumbles in the hand easily enough. I will dig some up and take some photos.
The glass is neither half full or half empty. It is too big. But this tiny ad is just right:
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