040120d

Cross-bedded a very fine micaceous sandstone, crossbeds made obvious by bright pink mica flakes, most equant grains are quartz, Cretaceous Rodessa Formation, Citronelle oil field, South Alabama, 11,500 feet below the surface, thin section photomicrograph, crossed polarizers.

041919c

A ripple made of mica and quartz, bright colors are mica and quartz is gray, thin-section photomicrograph, crossed polarizers, Rodessa Formation, about 2 miles below the surface, Citronelle Field, Alabama.