During the deposition of the Morrison Formation, the Ancestral Rockies had erroded down into wide open plains. Earth was a lot wetter at the time and had a a lot of marshes. When the marshes were present, there would be times when the sediment in the marshes were in an oxidized envirnment, meaning that there was oxygen in the environment. At other times, when there was a lot of decomposition of organic material, the environment would turn anoxic (lack of oxygen). This can be seen in the sediments in the alternating layers of green and purple layers. The green indicate and anoxic and the purple is oxidized. The color variation is due to the iron in the sediment which in the presence of oxygen will "rust" the iron and it shows up as purple in the sediments.

It was in this layer and this location that the first dinosaurs were discovered by Arthur Lakes, a teacher from Golden, CO.

A terrible fued