My Year of Darwin 5/10/2014: Petrified!

"Great prostrate silicified trunks of trees, embedded in a conglomerate, were extraordinarily numerous. I measured one which was fifteen feet in circumference: how surprising it is that every atom of the woody matter in this great cylinder should have been removed and replaced by silex so perfectly that each vessel and pore is preserved!" Charles Darwin, Voyage of the Beagle 

Man, what a find! These were ancient fir trees in Chile.