The lowest unit includes congomerate at the base with moderately rounded pebbles and coarse sand containing scattered pieces of fossilized wood. The conglomerate is overlain by reddish, maroon and gray shale and mudstone with plant fossils. There are also dinosaur footprints in the mudstone.
The reddish color of this unit, along with the types of fossils present indicate that these rocks were deposited in
an on land enviornment
The red color in rocks often indicates the presense of the iron-oxide mineral, hematite. This most commonly forms in environments that are exposed to oxygen in the atmosphere, and NOT in under-water environnments. Also, all of the fossils listed (plants, wood, dinosaur tracks) are things that would form on land, not in an ocean or lake.