An approximately 100 km² basin, which formed between 32 and 27 million years ago, preserves 150 meters of sediment in the Chilga area 60 km west of Gondar on the northwestern Ethiopian Plateau. These ancient sediments contain a wealth of fossil plants occurring in volcanic ash (deposited by air and water), streamside mud, and swamp deposits. Ashes preserve impressions of fruits, leaves, and stems along with petrified trees preserved in place; streamside clays preserve leaf, flower, and insect compressions along with in-place charcoalified tree trunks and stumps; and swamp deposits are represented by compressed plants, which form lignite. The Chilga sediments also preserve petrified forests with numerous trees in growth position. The plant fossil assemblages document diverse forests, from 20-35 m tall, of locally mixed composition, and representing families occurring commonly (legumes) and uncommonly (palms) in African forests today. Furthermore, Chilga sediments preserve unique assemblages of fossil bones representing animals limited to Africa. They include three families of elephants, primitive hyraxes, and the last occurrence of an extinct order of large, horned mammals known as arsinoitheres. Five main types of ancient soils reflect varied poor drainage conditions across a predominantly flat landscape, which also varied through time (as reflected by the presence of these five soil types through the vertical pile of sediments). The geological and fossil information together are consistent with the presence of a meandering river and ample rainfall to support lush vegetation. Over time, the region was subjected to intermittent ashfalls and laterally changing depositional environments. The plant, animal, and sedimentological information from the Chilga deposits significantly improve an otherwise limited Paleogene (65–23 million years ago) record from the Afro-Arabian continent.