Trace Fossils Plagiogmus and Skolithos in the Tintic Quartzite (Middle Cambrian) of Utah

A single slab of Tintic Quartzite from Weber County, Utah, contains three dimensional Plagiogmus traces, the upper surface of which are penetrated by Skolithos burrows. The occurrence of representatives of the Skolithos and Cruziana facies together suggests that this part of the Tintic was a facies intermediate between the two. Regional relationships as well as the occurrence of Middle Cambrian trilobites in beds immediately overlying the Tintic indicate a Middle Cambrian age for the fossils, thus answering questions posed by previous workers.