118 D. E. SAVAGE 



4. Chiroptera (bats) 



a. Earliest record in Eocene of North America and Europe 



b. Probable latest Mesozoic or Paleocene derivation from a 

 eutherian stock (Insectivora?) 



c. Bat-like forms are reported from the late Paleocene of North 

 America, but the group is too poorly known to conjecture as to 

 center of origin 



5. Primates 



a. Earliest record in middle Paleocene 



b. An early Paleocene or latest Cretaceous differentiation in the 

 radicle Eutheria 



c. Possibly originated in North America, but mammal-bearing 

 deposits as old as the early North American records are not 

 known on the other continents 



6. Tillodontia (extinct) 



a. Earliest record in upper Paleocene 



b. An early to middle Paleocene differentiation from unguiculate 

 (?) stock 



c. Possibly originated in North America, but evidence inconclusive 



7. Taeniodonta (extinct) 



a. Earliest record in lower Paleocene 



b. A probable late Cretaceous differentiation within the Eutheria 



c. Entire record of this group is in Nearctica 



8. Edentata 



a. Earliest record in upper Paleocene 



b. An early to middle Paleocene differentiation from unguiculate 



stock 



c. Probable Nearctic origination because the earliest forms known 

 lack dermal armor and have a less specialized skeleton; but early 

 and middle Paleocene records of mammals are lacking in 

 Neogaea, the center of mid-Cenozoic evolutionary radiation of 

 the Edentata 



9. Rodentia 



a. Earliest record in upper Paleocene 



b. Presumed origin from early or middle Paleocene unguiculate 

 stock, but annectents are completely unknown 



c. Possibly originated in Nearctica, probably in Holarctica, but 

 evidence is inconclusive 



10. Carnivora 



a. Earliest record in lower Paleocene 



b. Probably derived from a late Cretaceous eutherian group that 

 has been referred to the Insectivora or is not yet recorded; 

 possibly became a discrete group before the end of the Mesozoic 



c. Probably of Holarctic origin, possibly in Palearctica 



11. Condylarthra (extinct) 



a. Earliest record in lower Paleocene 



