Keywords: The king of the animal world 15 million years ago.jpg Charles D Walcott A Geologist's Paradise National Geographic Magazine Vol 22 pp 509 “521 image on page 517 http //babel hathitrust org/cgi/pt id uc1 32106005810137 California/Google 1911 Creator Charles Doolittle Walcott PD-old-80 Walcott A Geologists Paradise |