The Fort Union of the Crazy Mountain Field, Montana and Its Mammalian Faunas. E-book. Formato PDF George Gaylord Simpson   -  Forgotten Books, 2017  - 

The second and longer part Of the memoir is zoological and is devoted to definitions of all taxonomic groups which were originally described from this field or the conception of which is markedly affected by material from here, to discussion of the relationships and phylogeny of the mammals represented, and to description Of the specimens in the collection. Geology outside the area Of reference and mammals other than those definitely identified here are mentioned only for the sake of comparison.