Eocene Poplar Fossil Leaf With Insect Damage

Description: The Green River Formation deposits of Wyoming, Colorado, and Utah are best known for their immaculately-preserved fish, but other examples are known as well, as this specimen attests. This leaf from a tree of the Willow family which shows evidence of damage due to insect feeding. The damage here was done only a short time before the leaf was deposited in the stratum as shown by the fact that the holes do not have a dark edge which would have indicated that the leaf had scarred as a result of the attack. The presence of this tree is indicative of the lakeside environment in which it lived. Some 50,000 square miles of what is now Utah, Wyoming, and Colorado were covered by large lakes during the Eocene.