volcanoes, which buried mountains almost thorny cactus and spiny yucca grow. to their summits a long, long time ago. It consists for the most part of plains cov ered with sage brush and river valleys, In the Great Basin are two great depressionsDeath Valley and Mojave Desert-which lie sev These plants are peculiarly adapted to a dry climate. They have thick leaves and stalks which are very juicy. The juice is kept from drying out by the thick outer covering of the entire plant. Trace the Humboldt River; the Sevior River. eral hundred feet below sea-level. Find them. Locate the Colorado Plateau. What two rivers unite to form the Colorado River? Trace the basin of the Colorado. Trace the river and its tributaries, describing each. The Colorado plateau is cut up-dissected-by the wearing River and its action of the Colorado The Basin Region consists of vast that the wearing and weathering of the narrow valley sides are very slow; hence the walls of the canyon are almost perpendicular. (Page 83.) The highest parts of the plateau are covered with forests. There are many mesas, or remnants of what must once have been a much higher rock plateau. (Page 71.) You see that the great Western or Primary Highland, about which we studied on page 112, descends to the Basin Region as it extends northward from the Mex ican Plateau. From this basin it rises again in the Columbia and Colorado Pla teaus. The Rocky Moun tains mark the eastern, and the Sierra Nevada and Cas Between the high Sierras and the low Coast ranges is the valley of California. It is drained to the sea by two rivers. Trace them. This is a rich and fertile valley, although much of it is made so only through only through irrigation. Great vineyards are cultivated for the production of wine and raisins. (See picture on next page.) The Great Plains extend eastward from the Rockies, merging merging into the Valley of the Mississippi. The plains are broken by the Black Hills, the Missouri Heights, the Ozark Highland, and the dry Texan Plateau. Find each. HOMES IN THE BASIN REGION. The amount of rainfall on these plains is so uncertain from year to year that grazing has been found to yield a better and surer return in money than other farm occupations. The Black Hills are forest-clad, and rich in mineral deposits. The Ozark Mountains are noted for their lead ore. Forests grow on the river banks and on the higher parts of these plains. Trace the many streams which flow across |