Thursday, May 5, 2016
Thin section photomicrograph (image 2.5 mm wide), part of an ancient carbonate sand shoal. Later, a small mound grew on top of the shoal. Ooid grainstone.
Wednesday, May 4, 2016
Crinoid columnal in Mississippian fossil deposit, coated with two layers of calcite (dark rim). The fossil is in a former carbonate sand shoal that buried a mound made of corals, bryozoans, and crinoids. Photograph about 2 1/2 mm wide.