This issue features prehistoric creatures that lived on our continent around goo million years ago, in the early Cambrian Period of the Palaedzoic Era. At this time, organisms had not yet emerged from the water to live on land. They had, however, developed skeletons, shells and other external and internal hard structures. The fossils of the extraordinary early Cambrian creatures on the stamps were found in Emu Bay Shale deposits on Kangaros Island, South Australia. Nesonektris oltridges was a large vetulicolian (swimming chordate) that grew to around 18 centimetres in length. It had a streamlined body, a mouth opening at the front and a flexible tail probably used to propel it away from predators. The four centimetre-long lobopodian, informally known as the Emu Bay Shale Monster was a soft-bodied, velvet worm-like creature with protective spines on Its back and body segments bearing pairs of spiny fliter-feeding legs in the anterior body and short anchoring lobopods in the posterior part. The fierce-looking Anomalocoris doleyne was. at around so centimetres long, ane of the largest animals in the oceans at that time, and had svimming flaps running along its body, large compound eyes, and a single pair of segmented frontal appendages used to grasp prey. The predator Redlichio rex reached around 25 centimetres in length. Bigger than a dinner plate, this species is the largest trilobite from the Cambrian Period yet found in Australia. A predator, it had formidable legs with spines used for srushing and shredding food. As shown on the stamp.it may have hunted sther trilobites. Stamp and medallion illustration: Peter Thisler. Stamp typography jatan Wates, Australia Fest Design Studio. Cover design: Kerth Downes, Plaelad Photographs: courtesy Associate Professor Diego C Garcia Bellido (AU/SAM), Radlichis and Estaingia fossils from Emu Bay Shale (frontcover), drone image of the Emu Ray Shale fossil site at Bucs Quarry, Big Guily, Kangaros Island South Australia (innercard)