The canyons are largely the work of rivers, modified by glaciers that ran through them after the rivers had formed them.
Several varieties of poplar are found in the upper canyons, and trees of the willow-leaved species in the Humboldt Mountains often attain a height of 60 ft.
In the Great Plains region and in the TransPecos Province the rivers have cut deep canyons, and the character of the longer rivers in their upper courses varies from mere rivulets late in summer to swift and powerful streams during spring freshets.
In the canyons of the Edwards Plateau grow the pecan, live oak, sycamore, elm, walnut and cypress; on the hilly dissected borders of the same plateau are cedars, dwarf and scrubby oak, and higher up are occasional patches of stunted oak, called "shinneries."
On its slope, which rises abruptly from the Bitterroot Basin, glaciers have cut canyons between high and often precipitous walls, and between these canyons are steep and rocky ridges having peaked or saw-toothed crest lines.
Several smaller basins occur in Montana, all somewhat dissected and drained through narrow gorges and canyons by members of the Missouri system.
Where the volcanic formations were spread uniformly over the flanks of the mountains, the contrast between the canyons and the plain-like region of gentle slope in which they have been excavated is especially marked and characteristic. The eastern slope is very precipitous, due to a great fault which drops the rocks of the Great Basin region abruptly downward several thousand feet.
Above the basin floor; the eastern slope is more gentle, but both slopes are much scored by deep canyons, some of which have been modified in form by ancient glaciers.
It exhibits much evidence of powerful erosion, having deep canyons in its sides, and it bears evidence of previous glaciers.
Of the Neosho rivers are deeply carved by small streams, and in the western portion of this area, where the formation consists of alternating shales and sandstones, the easily eroded rocks have been carved into canyons, buttes and mesas.
Her laugh echoed down the rocky canyons of Zzz as the essence of abomination breathed his bloody last below her.
On its eastern slope the waters soon disappear within the bed of narrow canyons, but break out again at the foot in icecold springs that form the source of the Ruby and Franklin lakes; on its western side the descent is more gentle, and the waters form the South Fork of the Humboldt river.
There are also deep canyons which have been cut by the rivers in their present courses, especially by the Snake river and its tributaries.
Here the streams that drain the higher areas descend to the plains through narrow canyons in the mountain border, impassable for ordinary roads and difficult of entrance even by railways; a well-known example is the gorge of Clear Creek east of the Georgetown mining district.
The few rivers of the region must have reached the quiescence of old age iii the earlier cycle, but were revived by uplift to a vigorous youth in the current cycle; and it is to this newly introduced cycle of physiographic evolution that the deep canyons of the Plateau province are due.
In the new altitude of the mountain mass, its steep eastern face has been deeply carved with short canyons; and on the western slope an excellent beginning of dissection has been made in the erosion of many narrow valleys, whose greatest depth lies between their headwaters which still flow on the highland surface, and their mouths at the low western base of the range.
Glacial erosion has been potent in excavating great cirques and small rock-basins, especially among the higher southern surmounting summits, many of which have been thus somewhat reduced in, height while gaining an Alpine sharpness of form; some of the short and steep canyons in the eastern slope have been converted into typical glacial troughs, and huge moraines have been laid on the desert floor below them.
It appears in the cores of some of the western mountains, in some of the deep canyons of the west, as in the Grand Canyon of the Colorado in northern Arizona, and over considerable areas in northern Wiscpnsin and Minnesota, in New England and the piedmont plateau east of the Appalachian Mountains, and in a few other situations.
In most cases they reach the coast through deep valleys or profound canyons, and the transcontinental railways find their way beside them, the Canadian Pacific following at first tributaries of the Columbia near its great bend, and afterwards Thompson river and the Fraser; while the Grand Trunk Pacific makes use of the valley of the Skeena and its tributaries.
The edges of the protaxis are in general its highest parts, and the rivers flowing outwards often have a descent of several hundred feet in a few miles towards the Great Lakes, the St Lawrence or the Atlantic, and in some cases they have cut back deep gorges or canyons into the tableland.
Its depth is not great, at least as compared with the canyons upon the Colorado river system; it ranges from 600 ft.
In the neighbourhood are the Cave of the Winds, the Grand Caverns, charming glens, mountain lakes and picturesque canyons; and the Garden of the Gods, - approached by a narrow gateway between two tremendous masses of red rock 330 ft.
The two Cheyenne Canyons, with walls as high as 1000 ft.
The Niagara escarpment mentioned above, generally called "the mountain" in Ontario, is the cause of waterfalls on all the rivers which plunge over it, Niagara Falls being, of course, the most important; and in most cases these falls have eaten their way back into the tableland, forming deep gorges or canyons like that below Niagara itself, through which the water pours as violent rapids.
Towards the south margin of the Highlands notable instances of true canyons in the Old Red Sandstone are to be seen where the Isla and North Esk enter that formation.
Precipitous gorges or canyons often from 2000 to 5000 ft.
All the " gulches " or ravines leading down into the canyons were also worked over, with or without water.
The exquisite colour contrasts of the Cheyenne canyons near Colorado Springs, Boulder Canyon near the city of the same name, Red Cliff and Eagle River Canyons near Red Cliff, Clear Creek Canyon near Denver - with walls at places 1000 ft.
The most important stream is the Rio Grande, which, rising in southern Colorado, enters New Mexico through deep canyons near the centre of the northern boundary and continues southward across the entire state.
In the valleys there are usually about two snows a year and these quickly disappear; but on the mountain peaks and in the canyons the snow accumulates to great depths and forms a steady source of water-supply for the rivers.
It is dominated by high mountains, gashed by superb canyons of rivers, scarred with dry gullies and washes, the beds of intermittent streams, varied with great shallow basins, sunken deserts, dreary levels, bold buttes, picturesque mesas, forests and rare verdant bits of valley.
The surface of western Nebraska is characterized by high, barren table lands, broken by canyons, dotted with buttes, and dominated by some bold and lofty ridges.
The White river and Hat Creek have carved canyons in deep lacustrine deposits, creating fantastic cliffs and buttes, bare of vegetation, gashed with drainage channels, and baked by the sun.
In the foothills there are typical canyons, as along the Platte forks, and in the northern edge of the sand-hills Those of the upper Republican are the largest, those of the Bad Lands are the most peculiar; and the Niobrara tributary system is the most developed.
Those of the White system have opentrough valleys bordered by hills in their upper courses and canyons in their lower courses; others, notably the Gasconade, exhibit re 1 Counting the St Francis projection the length is 328 m.
By far the greater part of the high plateau district is drained by the Colorado river and its branches, the most important of which are the Green, Grand and San Juan, portions of whose courses lie in canyons of remarkable grandeur.
The Copper, the Susitna and its tributary, the Yentna, as well as the Skwentna, a tributary of the Yentna from the west, all run through picturesque canyons, and their upper courses are characterized by glacial and torrential feeders.
Thousands of Alpine glaciers from one to fifteen miles long fill the upper valleys and canyons of the mountains.
A fair variety of trees - cottonwood, sycamore, ash, willow, walnut and cherry - grow in thickets in the canyons, and each mountain range is a forest area.
These gradients enable the inconstant streams tributary to the Colorado to carve their canyons, some of which are in themselves very remarkable, though insignificant beside the Grand Canyon.
Provpee The province was uplifted and divided into great blocks by faults or monoclinal flexures and thus exposed to long-lasting denudation in a mid-Tertiary cycle of erosion; and then broadly elevated again, with renewed movement on some of the fault lines; thus was introduced in late Tertiary time the current cycle of erosion in which the deep canyons of the region have been trenched.
Lebanon, in the 1Vlaronite districts of Kesrawan and Bsherreh, where the gorges are veritable canyons, and the villages are often very picturesquely situated.