Bolaspidella jarrodi

Western Utah is the home of one of the best-known Cambrian fossil localities in the world. The slopes of Swasey Peak in the House Range, seen above, are composed of a rock layer known as the Wheeler Shale, with the overlying Marjum Formation forming the top of the peak. The Wheeler Shale and Marjum Formation, strata of Middle Cambrian age, are exposed throughout the House Range and nearby mountain ranges west of the town of Delta, Utah. The Wheeler Shale is named for a great bowl-shaped feature in the House Range known as the Wheeler Amphitheater, while the Marjum Formation is named for its outcrops at Marjum Pass, also in the House Range. Much of the Wheeler Shale is quite unfossiliferous, but certain layers contain abundant trilobites and other shelly fossils. The Wheeler Shale and Marjum Formation also contain a diverse biota of soft-bodied fossils, including many of the same taxa found in the more famous Burgess Shale.

Bollaspidella is a member of the order: Ptychopariida, a large heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second half of the Lower Cambrian, and the last species did not survive the Ordovician–Silurian extinction event.

References:

Wheeler Shale Formation
Marjum_Formation
Charles Doolittle Walcott
Ptychopariida