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This paper was orginally produced as part of a field guide for the 9th International Meeting of Early/Lower Vertebrate Paleontologists held May 20 - 27 at Northern Arizona University, Flagstaff, Arizona.  The field trip followed that meeting.  This text of this paper has been slightly modified and some additional graphic support has been added.
 

    The modern landscape of the western United States reveals a rich geologic history exposed across deep canyon walls and in towering mountain flanks.  The modern landscape has evolved since Eocene time and, with regards to the field trip area,  includes the Colorado Plateau, a high elevation and geologically stable feature that occupies much of eastern Utah and northern Arizona, and the Basin and Range which is typified by north-south trending mountains and valleys of Nevada and eastern Utah.  With surprising accuracy, these modern geomorphic provinces align well with geologic features of the past (Figure 1).  The western portion of the modern Colorado Plateau in Utah, for example, correlates well with the ancient position of Paleozoic continental and transitional deposition.  The Basin and Range province of western Utah, central and eastern Nevada largely coincides with Paleozic shelf, slope and basinal marine deposition, respectively.  Even the modern day boundary between these two geomorophic provinces, the Wasatch Front of central Utah, has a Paleozoic manifestation:  the flexural hinge of the continental margin (Figure 1). With these modern markers for a guide, we can easily explore the general stratigraphic realtionships of the Paleozoic.
    Departure from the central southern Colorado Plateau of Arizona along a west-northwest route into southern Utah crosses a thin but ever thickening wedge of Paleozoic sediments (Figure 1).  Traverse of the Hurricane fault system at Cedar City, Utah, a still active southern extension of the Wasatch Front with historic records of magnitude 5+ earthquakes, equates to passage into the Paleozoic geosyncline.  Further west lies the shelf-slope transition positioned near Eureka, Nevada (Figure 1).  Traveling north from Eureka to Elko in eastern Nevada parallels features of the Paleozic continental margn which trend north-south.  Returning eastward into Utah from northeastern Nevada transects shelf deposits which thin up to, straddle, and cross the Paleozoic hinge-line, again marked by the Wasatch Front, just east of Salt Lake City.  Shallow shelf deposits continue to thin along the northeasterly route to Logan, Utah, and grade into transitional deposits with excellent exposure in the Bear River Mountains and its’ canyons (Figure 1).  The journey south toward Green River, Utah, and Flagstaff, Arizona, traverses thining Paleozoic sedimentation with spotty or non-existant records of pre-Mississippian deposition and a post-Devonian record of local
basins with marine and sporadic continental deposition.  The planned field trip route disects many of the features just noted and more, including basins and structural elements that controled deposition during the Paleozoic (Figure 2).  Although the simplicity just presented is complicated by the results of eustatic fluctuations and Waltherian responses, platform progradation, paleogeography, and tectonic and structural elements, the preceeding framework is a reasonable guide that will allow the addition of some complexity.  By way of introduction, the following text outlines various structural and tectonic elements that exisited during the Paleozoic.