his own artificial lines with facility. The study of the natural system leads him directly to the perception of certain nodal points on the earth's surface, to hold which is to hold all the empire between them. Thus, if it be conceivable that any new Alexander should arise to struggle for universal empire, he would practically succeed (in the present state of artificial communication) when he had possessed himself of the Straits of Gibraltar, the Isthmus of Suez, the entrance to the Red Sea, the isthmuses joining North and South America. Similarly the great passes and intra-montane plateaus of the Rocky range involve in their possession the power to dictate to New York and California upon many of their common matters, and the ability at will to unite them by the strongest ties of national cohesion, or eventually break up vital communication between them. The West side of the Continent is overwhelmingly loyal in its animus; proud of the American Union and its own position in it. But the Pacific States will in time grow to be self-sufficient. They will grow, manufacture, import for themselves; and when that maturity arrives, the homogeneity of the two coasts will and should depend upon the degree of facility afforded to intercommunication. So long as it remains a formidable undertaking to pass between New York and San Francisco, so long will there develop an independence of interest and feeling which, however gradual and imperceptible, cannot fail to result in two distinct nations.

The value to the future statesman and engineer of such nodal points as we have mentioned, is well illustrated by a description of the South Pass occurring in ex-Governor Gilpin's interesting book, "The Central

Gold Region." Laramie Plains are a level of similar interest. This level is a justification of the Spanish name of the system,- Sierra Madre, or Mother-Range. It is one of a group of mothers occurring along the axis of the Range, out of whose loins come the grand rivers which irrigate the Continent. From the Plains of the South Pass, and the vast ranges on whose summit the plateau is upborne, flow the Missouri and the Yellowstone to the easterly; the Snake, or principal fork of the Columbia, to the westward; and in a direction south by westerly the Green, or main branch of the Colorado River. Either by themselves or their cañons and valleys, which radiate towards one common centre in the Plains of the Pass, these rivers facilitate communication between the Mississippi and the Great Salt Lake basins, offering a series of nearly connected galleries cr grades rather to the revision than to the reconstruction of the civil engineer. The Laramie Plains form another level, important for the same reasons, if not in the same degree. The level and its inclosing mountains form a reservoir for far less voluminous and extensive streams than those rising out of the South Pass plateau, but offer better opportunities for the study of the phenomena of the system than if their own were more complicated. The mountain mesa which has the Laramie Plains for its upper surface, is almost cinctured by the North Platte River. The South Platte has its origin in South Park; its net-work of tributaries may almost be said to inosculate on the north side with those running into Middle Park for the formation of the Blue Fork of the Colorado; the Blue Fork receives another system of tributaries running southerly from North Park, and this system again interpenetrates that of the tributaries

running northward to compose the North Platte in the area of the same Park. Behind that grim range of bare, black mountains which form the southern wall of the Laramie Plateau, the North Platte is winding in a general westerly direction out of the snowpeaks which nurture its infancy. Eighty miles west of the Laramie Plains summit level, it makes an abrupt bend to the north, and thence preserves this direction to the western butment of that noble range which forms the northern wall, taking in, near this corner, the Medicine Bow Creek, which has descended from a magnificent congeries of snow-peaks, to be climbed by us on the morrow, and has followed a higher terrace of the same slope as the North Platte across the entire west side of the mesa. A step further on, the North Platte receives the Sweetwater from the west, and, passing around a bastion of the Wind River system, turns nearly due east to enter the lower Plains near Fort Laramie, receiving en route innumerable further tributaries, all of which rise from the north slope of the Wind River system, excepting the Laramie River itself. This latter stream is formed by the junction of two forks, the Big and Little Laramie, both of which rise out of the Black Mountains, on the plateau's southern boundary, and traverse it completely from south to north, uniting nearly in its centre.

A careful examination of the best Government maps of this region will enable the reader to follow this description, and get an idea of the contour of the Laramie mesa, which may serve as the key to all other formations of the kind, including the Plains of South Pass and the three great parks south of Laramie. Upon such nodal points as these, all the internal

river systems of the Continent are centred. Their contour and position are the important facts of the range to the theoretical, the all-important ones to the practical student of physical geography.

Big and Little Laramie, where we crossed the Plain, flow nearly parallel and about fourteen miles apart. Their width, at the bridges maintained by the Overland Route, is about thirty or forty yards. Their banks, but especially those of the latter branch, are enameled with flowers of a brilliancy unequaled, but of titles unknown in my experience. One variety

was a scarlet vivid as flame, and at a distance resembled a salvia. The leguminaceae were represented by several plants bearing the richest mauve and purple blossoms; besides which I noticed some flowers seemingly allied to the larkspur, of a deep-blue shade, and sparingly interspersed among the profusion of the others. The sun was just on the western verge of the plateau as we reached Little Laramie; and the effect of his level rays upon the exquisite cool verdure of the grass, with all these brilliant flowers dashed in for the high tones, was something out of which to manufacture peaceful memories for a lifetime.

During the next seventeen miles the ground gradually grew less even; but the general characteristics of the plateau were preserved until twilight gave way to starlight, and we arrived at the station of Cooper's Creek. Here the moon rose, and revealed to us one of the loveliest little dells in all the Rocky Mountain scenery. Along the bottom of a shallow depression ran, crystal-clear and icy cold, a small stream, rising from the same Black range as the Laramie, and belonging to one of three classes which

abound in this immediate vicinity: the streams which lose themselves upon the Plain in "sinks," or lakes without outlet; those which penetrate the Black range to join the North Platte immediately; and those which flow thither indirectly, by emptying into Medicine Bow. For these three systems, the terrace including Cooper's Creek forms a nodal point on the small scale; to which of them the creek belongs, I am not positive. We ate our supper from the box of private stores, sitting dappled with the moon-shadow of the luxuriant cotton-woods which embowered the creek; and listening to its tuneful gurgling, or watching the silver flash of ripples break across an umber pool of shade, we could have forgotten that this was not the end of our wanderings.

The hoarse "All right!" of the driver startled us from our lotus margin. We had a great deal more before us; so we arose to shake the crumbs from our beards, and the romance from our souls. We turned back one lingering glance at the paradise of Laramie Plains. Far off we heard the shrill yelp of the coyote; and as far, a silver spark went shooting across the shadow of a grassy terrace, with that electric swiftness which denotes the antelope. The whole great level was powdered with silvery mist. The moonlight seemed to lie on the nearer grass in silvery globules. Moonlight was tangled into the texture of the grossest things. The ragged cotton-wood bark by the creek looked like strips of silver foil; the bleak station-house was soaked in a solution of romance, and might have been let for a palace to Rasselas ; there was antiquity and a sort of Gothic strength about the company's stables; while the very mules of the new relay seemed touched by the divinity of