I went and looked at the site and noticed that our geologist friend Tas was asserting that all the bad lying geologists are murmuring soft nothings to us about how rocks always take millions and millions of years to form, and here we have a bottle that fell into the ocean and that’s since been slimed by a concrete-like aggregate in just a few hundred years.

Geologists don’t insist that everything about rocks takes a long time. Volcanic magma can solidify mid-air when spattered molten from a volcano. One sees rocks full of bubbles, miles and tens of miles away from volcanos. The stuff is called scoria. Volcanic ash flows can weld themselves into a rock as they cool, and that can take just minutes. Going to somewhat slower processes, travertine laid down at hot springs in Yellowstone can accumulate at rates of up to 1 inch per week. It wouldn’t take millions of years to bury a bottle at that rate!

That said, sandstone doesn’t form overnight.