Fagus langevini (Beech) leaf plate 86mm, discovered in the McAbee Fossil shales which were sediments of an extinct shallow lake when a warm temperate climate in the northern hemisphere prevailed. The fossil record shows that this was a time when palm trees grew as far north as Alaska. Many plant species have described from the Tranquil shale, including deciduous, Conifer, Sassafras, Katsura and Ginkgo, and a diversity of insects, fish, and even rare, delicate feathers. The fossil shales record plants and trees, flora and fauna from an ancient prehistoric forest which lay close to mountains surrounding a large lake. In all probability, the leaves, flowers, seeds and insects of the forest had been transported into the lake by wind, rivers and streams where they sank to the bottom, eventually covered over with fine sediments and diatoms.
The fine sediments enabled fossilisation by carbonisation, preserving the specimens completely and in some instances, making possible detailed comparisons of the fossils to our modern-day flora and fauna. Many of the specimens discovered today have yet to be identified completely and named by science. The fauna and flora establish this ancient forest of the McAbee layers were much more diverse than our forest of today. From fossil deposits paleobotanists determine the perimeters close to the lake were predominantly forested with established genus types as elm, birch, alder and beech trees in the higher elevations spruce. firs and pine trees persisted, most of the type species discovered in the fossil beds are still extant today.