a pair of unusual trilobites termed "sail-spined" by some due to the dramatic row of axial spines found in this species. While some are larger, these are in an excellent state of preservation, sure to become the cornerstone of any trilobite collection. They are well matched in size, and the different poses show off their spiny armament to good advantage. These spines were a good defense against the fish of their day, affording quite a mouthful for any predator with the temerity to attack