Since it was an unknown trilobite to me I consulted the BEST trilobite fossil site on the internet Sam Gon III's http://www.trilobites.info/. It appears to me after looking at his drawings and images on the site, this speciment might be an Elrathia kingii. Specifically, the site lists it as Order: Ptychopariida, Suborder: Ptychopariina, Superfamily: Ptychoparioides, Family: Ptychopariidae. The site has a picture gallery with references to pictures on another site http://www.trilobite.com/ which sells Elrathia kingii trilobites that lived during the Middle Cambian in Utah. Also I believe it or another site noted that this trilobite is the most common one sold today that is intact.
Click on pictures to view larger version.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjQV_t_q0ouyBmenOHnhXIpJHGu1QUBfjzKcYI_ceLaXkKlnGOd3PgFwqIWvXg2Nw-xjBByPuy60cd-pjO6pYopQ8jkw4nqL5ACMbTQjDJ4TkE7ia0_Zh2P7hoS5428ErN_TI2MfOEY_mN/s400/LSC-trilobite-front-cephalon-view.jpg)