Growth rings in an exposed CaCO3 outcrop. The whole thing looked a bit like a stump. Actively forming rock. The spikes are about 1cm across. The source of the dissolved CaCO3 is the Madera Formation. Another view of the first rock. The whole thing was full of funnels or tubes, from these big ones to about 2mm in diameter.
Science fiction, politics, cartoons, and whatever I want to talk about. With chickens!