When the Navajo Sandstone was deposited, Utah resembled the present-day Sahara. Over time, deposition in this sand sea ceased and erosion ensued creating the surface on top of the Navajo Sandstone called the J-1, or Jurassic 1 unconformity. After this erosional period, deposition resumed with an interior seaway in Utah called the Carmel Seaway. Shoreward of this seaway, dunes began to form again. These rocks are preserved in the rock record as the Temple Cap Formation, Carmel Formation, and Page Sandstone. In some areas, the J-1 unconformity is difficult to locate because the rocks above and below it look the same. XRF analysis, lab and field portable, has the potential to show differences in the chemistry of the Navajo Sandstone, Temple Cap Formation, and Page Sandstone, so that the J-1 unconformity can be located with confidence. Preliminary results are quite promising.