Keywords: Cenozoic mammal horizons of western North America BHL45549382.jpg Cenozoic mammal horizons of western North America 45549382 163354 86403 Foldout http //www biodiversitylibrary org/page/45549382 10 5962/bhl title 86403 Geological Survey U S ; Matthew William Diller; Matthew William Diller; Osborn Henry Fairfield Public domain The BHL considers that this work is no longer under copyright protection <br> Biodiversity Heritage Library Check categories 2015 October 31 PD-old-70-1923 Cenozoic mammal horizons of western North America Images uploaded by Fæ Files from the Biodiversity Heritage Library Biodiversity Heritage Library Ernst Mayr Library of the MCZ Harvard University collection |