Title from caption.
At head of title: Article 3.
Date of publication: Feb. 14, 1905. Cf. introd. text to v. 21.
Specimens collected by Albert Thomson from the White River formation in S.D.; Eutypomys thomsoni from the Lower Oreodon beds at Quinn Draw; Heteromeryx dispar from the Middle Titanotherium beds at Indian Creek; both on the Cheyenne River.