Bridgerian

Notharctus is a genus of adapiform primate that lived in North America and Europe during the early to middle Eocene. left|thumb|N. tenebrosus (left) compared to Plesiadapis|Plesiadapis cookei (right), a plesiadapiform. Both come from [[Eocene Wyoming, though the latter is slightly geologically older (Museum of Natural Sciences, Brussels).]] The body form of Notharctus is similar to that of modern rats. Its fingers were elongated for clamping onto branches, including the development of a thumb. Its spine is flexible and the animal was about in length, excluding the long tail.

Diacodexis is an extinct genus of small herbivorous mammals belonging to the family Diacodexeidae that lived in North America and Europe from 55.4 mya to 46.2 mya, existing for approximately .

Smilodectes is a genus of adapiform primate that lived in North America during the middle Eocene. It possesses a post-orbital bar and grasping thumbs and toes. Smilodectes has a small cranium size and the foramen magnum was located at the back of the skull, on the occipital bone.

Ignacius is a genus of extinct mammal from the early Cenozoic era. This genus is present in the fossil record from around 62-33 Ma (late Torrejonian-Chadronian North American Land Mammals Ages). The earliest known specimens of Ignacius come from the Torrejonian of the Fort Union Formation, Wyoming and the most recent known specimens from Ellesmere Island in northern Canada. Ignacius is one of ten genera within the family Paromomyidae, the longest living family of any plesiadapiforms, persisting for around 30 Ma during the Paleocene and Eocene epochs. The analyses of postcranial fossils by pale