0 a simple, flat sea creature that lived in the earliest period of life on earth, with a hard outer layer and a body in three parts
Some, such as those on brachiopods, trilobites and chitinozoa, record information pooled by many specialists; others are the work of one or a few workers.
Though commonly observed, blindness in trilobites remains difficult to explain in terms of adaptation.
The trilobites are disarticulated and generally fragmentary, which may indicate that they have been subjected to post-mortem transport.
Distribution of trilobites within these formations is random, and boundaries between the lithostratigraphic units are typically not exposed.
The trilobite was collected from a bed that is 28 cm thick, composed of limestone (moderately resistant micritic mudstone to wackestone).
The similarities are observed on the genus level, whereas on species level, trilobites from all these areas display a distinct endemicity.
The latter is well illustrated, with comments on faunas and facies, and listing the trilobites which have been found in particular formations and members.
Many specimens are incomplete, and this, together with their co-occurrence with fragmentary trilobites, spicules of sponges, sclerites of chancelloriids and other shelly organisms, suggests transportation.
