Undivided Keyser and Tonoloway Formations occur in the southern and southeastern parts of the Buffalo Creek watershed. The Hamilton Group occurs in a small portion of the southeastern part of the watershed. Undivided Onondaga and Old Port Formations also occur here, but take up a bigger area in the watershed. The Bald Eagle Formation occurs in small parts of the western and northwestern areas of the watershed. The Juniata Formation occurs in the same areas as the Bald Eagle Formation, as well as part of the northern part of the watershed. However, it takes up more area than the Bald Eagle Formation. The Reedsville Formation also occurs in the western and northwestern parts of the watershed. The undivided Bloomsburg and Mifflintown Formations occur in a zigzagging band that goes from the northeastern to the southwestern part of the watershed. The Clinton Group occurs in a zigzagging band immediately north of the Bloomsburg and Mifflinville Formations. It also occurs in a few scattered areas in the northeastern and western parts of the watershed. The Tuscarora Formation occurs in a zigzagging band immediately north of the Clinton Group. The Wills Creek Formation occurs in parts of the southern and northeastern areas.