Colorado National Monument - May 2011 January 19, 2013 Colorado National Monument lies just West of Grand Juntion, CO, near the border between Colorado and Utah. The so-called "Coke Ovens", also known as the "Haystacks". The stacks are composed of Wingate Sandstone about 200 million years old, with caps composed of harder material called the Kayenta Formation. Another view of the Coke Ovens from below in early morning. "Claret cup" cacti in bloom. Independence Monument - a 450-foot high fin of Wingate Sandstone with a Kayenta Formation cap is all that is left of a wall that once stretched across the canyon. Collared Lizard, Crotaphytus collaris. Collared lizards feed mostly on insects, and can run on their hind legs.