D Daemonelix [33], [69], [70], [86] Daphoenodon [20-21], [22], [32], [38] Darwin, Charles [43], [44], [45] Devil’s Corkscrew [76] Devils Tower National Monument, Wyoming [90] Devonian period [46] Diceratherium [24]. See also [Menoceras] Dinohyus [20-21], [22], [30], [87] Dinosaur National Monument, Colorado and Utah [42], [48], [88] Drought [35], [36], [50-51]
E Ecology [53], [61-73] Entelodon [30] Entelodont [30] Eocene epoch [25], [27], [29], [31], [46], [49], [53], [63], [88] Equus [63] Excavations [38], [39]
F Field Museum of Natural History [87] Flora [7], [10], [53], [54-59], [60], [71-73] Florissant Fossil Beds National Monument, Colorado [53], [88], [89] Folsom, New Mexico [14]; spearpoint, [17] Fort Laramie National Historic Site, Wyoming [90] Fort Robinson State Park, Nebraska [50], [77] Fossil Butte National Monument, Wyoming [89] Fossils [38-41], [47], [86-89]
G Geological Museum, University of Wyoming [86] Geology [35], [46], [47-52] Geese, Canada [82] Gerenuk [29] Gering Formation [50] Gopher, pocket [84] Graham, Elisha B. [10] Graham, Mary [10-11] Grasslands [26], [35], [51], [61], [71-72] Gregorymys [33] Guan [28]
H Hagerman Fossil Beds National Monument, Idaho [89] Harrison Formation [23], [50], [63] Hawk [56-57], [60]; marsh [83]; nighthawk [83]; Swainson’s [81] Horses [62-63], [66-67]. See also [Merychippus], [Miohippus], [Parahippus], [Protohippus] Hutton, James [45]
J Jackrabbit [84] Jefferson, Thomas [42] Jewel Cave National Monument, South Dakota [91] John Day Fossil Beds National Monument, Oregon [89] Jurassic period [46]
K Killdeer [83]
L Laboratory [40-41] Lamarck, Jean-Baptiste de [43] Laramide Revolution [49] Linnaeus, Carolus [43] [Little Bighorn Battlefield National Monument] [92] Lucretius (Titus Lucretius Carus) [42] Lyell, Charles [42], [43], [45]
M Map [78], [79] Marsh, Othniel C. [8], [9], [11] Marsland Formation [50], [51] Matthew, W. D. [52] McJunkin, George [14] Meadowlark, western [83] Meniscomys [32-33] [Menoceras] [14], [20-21], [22], [24], [25], [36], [38], [51], [86], [87] [Merychippus] [52], [58-59], [60], [62-63] Merychyus [20-21], [22] Mesozoic era [46], [47-49] Miocene epoch [46], [49-52], [71-73]; animals of [20-37], [62], [63], [64-69], [70]; birds of [28] [Miohippus] [25-26], [27], [64], [66-67] Mississippi Embayment [35], [49] Monroe Creek Formation [50] Morrison, Colorado [48] [Moropus] [20-21], [22], [29-30], [86-87] Mount Rushmore National Memorial, South Dakota [91] Museum of Comparative Zoology, Harvard University [87] Museum of Geology, South Dakota School of Mines and Technology [86] Museums, fossils at [86-87]. See also [American Museum of Natural History], [Carnegie Museum]
N Nanotragulus [27-28] National Park Service [17], [88-92] Nighthawk [83] Nimravus [32] Niobrara River [7], [16], [23-24], [36], [37], [50], [54-55], [60] North Platte River [52] Nothocyon [32], [33]