The ectoderm is the outer layer and encloses the body and mouth. Also, the ectoderm secretes a skeleton in corals. The endoderm, the inner layer, digestes food trapped by the tentacles. Another characteristic of cnidarians is that they can alternate between mobile and sessile lifestyles by alternating their generation reproduction. During a cnidarian's life, it will live both as a sessile polyp attached to substrate, and as a mobile medusa.
Corals spend the majority of their life as a polyp, and jellyfish as a medusa.
Additionally, the corals found in the Whitewater formation are entirely marine. Today, corals are found on reefs, where they are utilized as excellent indicators of climate and latitude. This is another example of Protaraea richmondensis . Protaraea is a compound coral that grows as a crust on other objects. This specimen displays that well.