Systematic catalogue of vertebrata of the Eocene of New Mexico, collected in 1874

The present essay completes the determination of the species of vertebrata obtained by the geographical survey under your charge in the Eocene formation of New Mexico during the field-season of 1874. The descriptions which have already appeared in your [George M. Wheeler] report to the Chief of Engineers, as published in the annual report of the latter for 1874, are not now repeated. The total number of mammalia is forty-seven species, of which the present report introduces twenty-four for the first time.