than north-south. Among the peaks of the Central Rockies, which include Grand Teton and Yellowstone national parks, are Gannett Peak (4207 m/13,804 ft high), Grand Teton (4197 m/13,771 ft high), and Fremont Peak (4185 m/13,730 ft high).
             The Northern Rockies are in northern Idaho, western Montana, and northeastern Washington. They include the Sawtooth, Cabinet, Salmon River, and Clearwater mountains and the Bitterroot Range. The loftiest points in the section, which includes Glacier National Park, are Granite Peak (3901 m/12,799 ft high) and Borah Peak (3859 m/12,662 ft high).
             The Canadian Rockies, located in southwestern Alberta and eastern British Columbia, are composed of a relatively narrow belt of mountain ranges that terminates at the Liard River lowland in northeastern British Columbia. The peaks of the section, which takes in Banff, Jasper, Kootenay, Waterton Lakes, and Yoho National Parks, include Mount Robson (3954 m/12,972 ft high), Mount Columbia (3747 m/12,294 ft high), and The Twins (3734 m/12,251 ft high). Slopes generally are very steep, and there are numerous glaciers.
             The Rocky Mountains are a geologically complex system with jagged peaks as well as almost flat-topped elevations. The Rockies were formed mainly by crustal uplifts in comparatively recent times, during the late Cretaceous and early Tertiary periods, and later were reshaped by glaciation during the Pleistocene Epoch. Today the Rockies receive moderate amounts of precipitation, most of which occurs in the winter. Lower levels are covered chiefly by grassland, which gives way to extensive forests, principally of conifers. Above the woodland is a zone of grasses and scattered shrubs. Most peaks have little vegetation around the summit, and some have a year-round cap of snow and ice.
             The Rockies are sparsely populated for the most part and contain few cities. The principal economic resources of the mountains are minerals, such as coal, copper, gold, ir...