Rare Lyriaspis sigillum Trilobite from Cambrian of Australia

Description: Well-preserved example of a member of the Order Ptchopariida missing a small amount of the left pleural lobe and the genal spines, a feature often not preserved intact. This one comes from Mount Isa in Australia. 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. Trilobites from Australia are not often available to collectors, and this represents the only example of the taxon I have been able to secure.