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While researching what caused the current invertebrate fossil of the month to have such a wonderful iridescence (www.thefossilforum.com), I came across some interesting info on preservation of color patterns in fossil shells. In Northern California where I live, most of the color of a fossil shell disappears after a few thousand years. The pattern of color is gone in a couple million years. While in Texas, I collected Texigryphea from the early Cretaceous that still had color patterns of dark radial bands. Finding a paper about Devonian brachiopods with color patterns surprised me. See: http://www.bioone.org/doi/full/10.4202/app.2010.0066 “First Colour-Patterned Strophomenide Brachiopod from the Earliest Devonian of Podolia, Ukraine” by Andrzej Baliński, found in Acta Palaeontologica Polonica 55(4):695-700. 2010. The first figure below shows the spotted pattern found on the convex shell of a strophomenid brachiopod from Ukraine. Wow, what a camouflage! The brachiopods blended right in against the light-colored rock with dark spots. I am reminded of well camouflaged modern mottled and spotted moths that are hard to see when they are on certain trees and rocks. The second figure shows a variety of color patterns found in fossil brachiopods. The paper suggests that brachiopods with colors and patterns occur in shallow water in the photic zone and in areas with warmer water. Few are found in cold polar waters. A similar distribution of colored shells and mollusks exists today. Shallow tropical species are very colorful while polar and deep water species are not. Show us some of your older fossil shells with colored patterns: Cretaceous and older.