060719d

Twinning in plagioclase feldspar sand particle, crossed polarizers, Rodessa Formation, Citronelle Field, Alabama, scale bar 25 micrometers (25 1000's of a millimeter)

022119b

Core of the Smackover Formation in West Appleton Field, south Alabama. Microbial boundstone (lower half) overlain by laminated carbonate sand consisting primarily of fecal pellets of burrowing shrimp (upper half). Dime for scale.