Introduction: We took a geological EVA to Skyline Rim where the upper Cretaceous Mancos Formation is exposed.

Geological Description: The outcrops along a route from the Hab to Wpt. 113, expose from the upper Jurassic Morrison Formation to the upper Cretaceous Dakota Formation. The Dakota Formation unconformably overlies the Morrison Formation.

The outcrops along a route from Wpt. 113 to 140 expose a stratigraphic sequence from the Dakota Formation to the lower part of the upper Cretaceous Mancos Formation. The Mancos Formation lies conformably above the Dakota Formation. Skyline Rim exposes a transition from the Tununk Shale Member to the Ferron Sandstone Member of the Mancos Formation. The Tununk Shale Member mainly consists of light gray marine shale and fine-grained light gray sandstone. The Ferron Sandstone member mainly consists of brown gray, marine, fine-grained, crossbedded sandstone.

(Click Image for Detailed View)
Sample 1	Sample 2	Sample 3

Samples: We failed to find Mollusca fossils except Gryphaeidae at Wpt. 112. We collected what appear to be rounded calcareous nodules at Wpt. 140. We estimate that they are from the Tununk Shale Member. The nodules are 2 to 7 cm in diameter and soluble in diluted hydrochloric acid. They appear similar to "Desert Rose". But we could not be certain and we are requesting opinions from the Remote Science Team geologists.