Before revision: Like the Burgess Shale, the Waukesha Biota, from the Silurian of Wisconsin, preserves many soft-bodied organisms, such as this possible leech .
After revision: Like the Burgess Shale, the Waukesha Biota, from the Silurian of Wisconsin, preserves many soft-bodied organisms, such as this cycloneuralian worm .