Description: This unusual specimen shows 3 legs from what must have been a fairly large arthropod. They have a strong resemblance to those thought to belong to Sidneyia, a large arthropod better known from the Burgess Shale (see: Briggs D.E.G., and R.A. Robison. 1984). Whatever the case, to my knowledge these are the ONLY examples available ANYWHERE.

Reference: Briggs D.E.G., and R.A. Robison. 1984. Exceptionally preserved non trilobite arthropods and Anomalocaris from the Middle Cambrian of Utah. University of Kansas Paleontological Contributions, Paper 111:1-24.