 Much of the Plunketts Creek valley ( and those of its tributaries ) is composed of various glacial deposits . <unk> to the mouth , there are large deposits of alluvium , as well as alluvial fan and alluvial terraces . Many of the glacial deposits are associated with the Wisconsin <unk> , with <unk> drift and till , as well as <unk> present . The alluvium is " 10 feet ( 3 m ) or more thick in the lower reaches of the Plunketts Creek valley " , but only " 6 feet ( 2 m ) thick in <unk> tributary valleys " . The <unk> is described as " <unk> sand and gravel that form terrace remnants along the flanks of Loyalsock Creek and Plunketts Creek valleys " . 
