Australian Xystridura st-smithi Trilobite

Description: This is a nicely preserved specimen. It has retained the free cheeks, which are normally not preserved. Some of the richest ore-bodies in Australia occur in a great mass of severely deformed and altered (metamorphosed) rocks at Mt Isa in north-west Queensland, One rock unit, originally shale deposits, contains abundant fossil micro-organisms, interpreted as blue-green algae. The trilobite beds date from the Middle Cambrian, around 520 million years ago, and they rest directly and unconformably on older metamorphic rocks such as those containing the Mt Isa orebodies.