Several recently discovered fossil specimens add to our knowledge of plesiadapiform primates.Micromomys willwoodensis, new species, is a diminutive microsyopid from the early Eocene (early Wasatchian) Willwood Formation of the Clark's Fork Basin, Wyoming. It is larger and more specialized than late PaleoceneM. vossaeandM. silvercouleei. Elwynella oreasis a new genus and species of paromomyid from the middle Eocene (early Bridgerian) Aycross Formation of northwestern Wyoming. It is most closely related toPhenacolemur, but differs from all other post-Tiffanian paromomyids in retention of P3and in details of incisor morphology and molar trigonid structure. New specimens of the microsyopidTinimomys graybulliensisare described, including a nearly complete dentary from the Wasatchian of the Bighorn Basin and the first record from probable Clarkforkian (latest Paleocene–earliest Eocene) beds of the Powder River Basin. The first Wasatchian specimen ofPlesiadapisis described and illustrated.