Colorado River, canyons, 4; canyons a barrier, 316; canyons avoided, 17; crossed with difficulty, 314; Derby explores to Yuma, 315; final problem, 320; first steamer on, 315; headwaters of, 4; length of, 4; map showing Marble-Grand Canyon, 326; Oñate arrived at it, 116; only one way to explore it, 314; point where Powell's men left him, 326; Powell desires to explore it, 320; remained unknown till Powell, 18; Sumner and Hawkins the only men to go all the way from Green River Valley to tidewater, 325; the close canyons, 322; tidal bore, 249; unbroken, 250, 314; valley, 6; verticality of walls, 324 Colorado River, Little, 116 _Colorado_, steamboat, 315 Colter, his race for life, 194; through the geyser region of the Yellowstone, 196; trapper, 194 Columbia River, Aguilar at mouth of, 142; bar, 142; discovery by Heceta, 142; first at mouth of, 4; first news of, 133; Fishing and Trading Company, 283; Great Britain claims mouth of, 219; rumours of, 138; visited by a native of Louisiana, 140 _Columbia_, ship, 4, 150 Comanche, tribe, where classed, 63; and Kiowa intimately associated, 64; house, 68 Comal (comalli), 267 Compagnie d'Orient, 138 Conception River, name applied to the Mississippi, 133 Concrete made with clay and gravel, 68 Conejos, Rio, Pike builds fort there, 189 Conflicting territorial claims, 155 Congress, generosity of, 303; passes railway bill, 328 _Constitution_, ship, sent to convoy the Tonquin, 199 Continental divide, 2 Contractor, chief, of Union Pacific Railway, 330 Cook, Captain, doubts existence of North-west Passage, 148 Cooper goes to Santa Fé in 1822, 257 Copper mines in New Mexico, 267 Corazones, Valle de los (Valley of the Hearts), 107 Coronado, Francis Vasquez de, 109; arrived near Kansas City, 126; expedition projected, 108; expedition, 110; finds buffalo robes at Cibola, 34; goes east, 112; goes with Marcos to see Mendoza, 109; injured, 113; referred to, 183; returns to Mexico, 113; returns to Tiguex, 113 Corralling buffalo, 46 Cotton cultivated, 93 Coues, discovers Fowler's journal, 235; suggestion as to Pike's real intentions, 184 Council Bluffs, 222; Clyburn walks there, 245 Coureurs de bois, 136 Cree tribe, where classed, 63 Creek tribe receive white refugees, 262 Crook, General, 266 Crooks, Ramsay, with Wilson Price Hunt, 205 Crooks, rejoins Hunt, 212; starts back, 210