Next to the deer comes the antelope, formerly so common on the Great plateaus. This, the pronghorn antelope, as it is usually termed, is about the size of the domestic sheep, but with long slim legs, and is a most active and exceedingly graceful animal. Its true home is on the treeless plateaus east of the Rocky Mountains, but its range extends from Saskatchewan to northern Mexico, and from the Prairie plains to the Cascade Mountains in Oregon. It has steadily decreased in number, especially during the last quarter of a century, and is now no longer seen in the large bands that were formerly an attractive feature of the sea-like plains over which it travels seemingly with the freedom of a bird. The animals thus far referred to have their range determined mainly by the broader features of climate, but not in a conspicuous way by the relief of surface. They inhabit mountains, plateaus, and plains alike, as is shown most conspicuously in the case of the wapiti, which formerly grazed in large herds on the prairies of the Mississippi Valley, and has been killed at an elevation of over 10,000 feet in the Pacific mountains. Not so, however, with the mountain-climbers whose names follow, which have their chosen "station" on the mountains at timber-line and ascend as far above that horizon as vegetation grows. _The Bighorn or Mountain-Sheep._--The bighorn, of which three species are now recognised, has its home in the Pacific mountains from northern Mexico to central and northern Alaska. Its vertical range is also great, as it has been seen on the precipitous walls of the Grand Canyon of the Colorado, but a few hundred feet above sea-level, and about the summits of the peaks of Colorado and in the Sierra Nevada and Cascade Mountains at elevations of from 10,000 to 13,000 feet. An exception to the fact that the bighorn is usually found on rugged mountains and is most at home on seemingly inaccessible cliffs is furnished by bands which live and appear to thrive amid the Bad Lands along the Missouri River, some 400 miles to the eastward of the Stony Mountains.