Sixty million years ago, the Mojave Desert of southern California was blanketed by a lush tropical forest. Where desert tortoises and sidewinders now roam, early mammals thrived alongside crocodiles and river turtles on a coastal plain. For decades, fewer than a dozen fragmentary fossils were known. Thanks to hundreds of new specimens uncovered by the Alf Museum, our picture of this ancient world is now much clearer. A scientific paper, just published in the journal American Museum Novitates, details 18 kinds of fossil mammals from this time, three of them completely new to science. These include California’s oldest primate as well as relatives of modern hoofed mammals.