No – not a shindig in Wales but a reference to Cambrian fossils at www.livescience.com/44654-first-fossil-blood-vessel-arthropod.html …. where it has been found that creatures living 520 million years ago had a sophisticated heart and blood vessel system similar to lobsters and other creatures in the modern world. The remarkable fossils come from a site in Yunnan Province in China which preserved intact the blood vessel system.
Arphropods come in a wide range of shapes and sizes but their basic body plan is about the same now as it was in the Cambrian- if not precisely the same. These particular fossils were found in what is known geologically as mudstone – basically mud that has hardened and become rock like. In other words, they were preserved in a massive wedge of mud – buried immediatelyh as other soft body parts were found at the site in Yunnan as well – including eyes, guts, and brains. The site is the Chinese equivalent of the Canadian Burgess Shale deposits.