TONTO NATIONAL MONUMENT.

The Tonto National Monument was created by proclamation dated December 19, 1907. It is located in Gila County, Ariz., and embraces two prehistoric ruins of cliff dwellings located somewhat less than 2 miles south of the Salt River Reservoir constructed by the Reclamation Service in the valley of the Salt River within the Tonto Basin, and is about 5 miles southeasterly from the town of Roosevelt. The prehistoric ruin is situated in the high, flaring en

FIG. 23.-Gila Cliff-Dwellings National Monument, within Gila National Forest, N. Mex., embracing NE. of sec. 27, T. 12 S., R. 14 W., New Mexico principal meridian and base.

trance to a large, shallow cavern, is three stories high, approximately 60 feet wide and 30 feet deep, and contains 14 or more rooms.

GRAND CANYON NATIONAL MONUMENT, ARIZ.

A considerable portion of the area set aside by the proclamation creating this national monument is covered by three different proclamations, one of which created the Grand Canyon Forest Reserve, one the game preserve embracing that part of the national forest north of the river, and the third the monument proclamation. It is be

lieved that the most wonderful portion of the canyon is contained within the present limits of the national monument and game preSteps have been taken to create a national park of the Grand Canyon of the Arizona, and a bill (H. R. 6331) providing for such purpose was introduced in Congress April 20, 1911, and is now pending before that body. The Association of American Geographers has recommended that the above-mentioned park be designated as Powell National Park, and the Geological Society of America

FIG. 24. Tonto National Monument, unsurveyed sec. 34, T. 4 N., R. 12 E., Gila and Salt River meridian, Ariz., containing 640 acres.

has approved the naming of the national park in the Grand Canyon. of the Colorado after its explorer, Maj. J. W. Powell.

JEWEL CAVE NATIONAL MONUMENT.

Jewel Cave, which is located 13 miles west and south of Custer, the county seat of Custer County, S. Dak., was discovered on August 18, 1900, by two prospectors, Albert and F. W. Michaud, whose attention was attracted by the noise of wind coming from a small hole in the limestone cliffs on the east side of Hell Canyon. In the hope of discovering some valuable mineral and the source of the wind, these men, in company with one Charles Bush, enlarged the 11355° -INT 1911-VOL 1-46

opening. Jasper and manganese are found in the cave, but to what extent is not definitely known.

The prospectors have followed the main descending wind passage for a distance of 1 miles, which point the explorers believe to be

FIG. 25.-Grand Canyon National Monument, within Grand Canyon National Forest, Ariz.

from 600 to 700 feet below the entrance, and have explored numerous side galleries and passages. However, the cave is far from being fully explored.

The cave, as far as known, is located in limestone formation and is apparently the result of action of water. A prominent geologist who visited this cave believes it to be an extinct geyser channel. The cave, as far as explored, consists of a series of chambers, connected by narrow passages with numerous side galleries, which increase in size as the distance from the entrance becomes greater.

The explorers have been careful observers of the action of the wind within the cave. They have discovered that ordinarily the wind blows in and out of the cave for regular periods, the periods of

FIG. 26.-Jewel Cave National Monument, within Black Hills National Forest, S. Dak., Tps. 3 and 4 S., R. 2 E., Black Hills meridian.

blowing in and out being 15 hours each, although they have known the periods to be of 72 hours' duration. Other wind passages have been discovered in the vicinity of the cave.

WHEELER NATIONAL MONUMENT, COLO.

The lands embraced in this national monument are situated near the headwaters of the middle fork of Bellows Creek, a northern tributary of the Rio Grande del Norte, about 10 miles northeast of

Wagon Wheel Gap, Colo., and 2 miles south of the crest of the Continental Divide.

The tract lies on the southern slope of the ridge which forms the crest of the Continental Divide. It is traversed from north to south by numerous deep canyons with very precipitous sides, the intervening ridges being capped by pinnacle-like rocks, making it practically impossible to cross the tract from east to west, even on foot. There are also many crevices cutting the ridges transversely, making an intricate network of ravines separated by broken precipitous ledges and broken mesas.

FIG. 27-Wheeler National Monument, within Cochetopa and Rio Grande National Forests, Colo., T. 42 N., R. 2 E., New Mexico principal meridian and base.

It is probable that the formation found here is the result of a succession of outpourings of lava and showers of volcanic ash which have left a series of nearly horizontal strata of varying degrees of hardness. Numerous pebbles and breccia of a flint-like rock are imbedded in the softer lavas which were probably gathered up by the flowing lava mud from the original bedrock. The formation is for the most part scoriaceous tufa and trachyte, with some rhyolite. The effect of erosion on this formation has been to cut it into sharply defined forms of many kinds. The harder broken rocks imbedded in the lavas have acted as veritable chisels, greatly accelerating erosive