Students went on a field trip to Kalodir, a site where with exposed sediments that are over 17 million years old. After chipping away sediments students recovered impressions of leaves and other plant parts. Impressions occur when, let’s say a leaf, drifts to the lake bottom where it is covered with fine sediments such as clay and silt. Over time the water disappeared and the sediments around the leaf hardened. Even though the organic matter that made up the leaf decomposes, the leaf left an in-print behind. This “impression” is what students found. Sometimes, and under certain conditions, plant parts do not decomposes but are preserved. This type of fossil is called a “compression”.