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| Moving up section, the Point Lookout sandstone is overlain by the Menefee Formation (show exposed in this road cut along the main park access road). The Menefee Formation contains interbedded layers of sandstone, mudstone, and shale with some soft coal (sub bituminous coal to lignite in grade). Plant fossils and coal layers indicate that the sediments of the Menefee Formation were deposited in floodplain and coastal swamp settings, with massive cross-bedded sandstone layers depicting deposition in migrating stream and river channels. These deposits accumulated along the western shore of the diminishing Western Interior Seaway about 75 million years ago. This view is along the North Rim section of the park access road. |
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