Returning next day from Culebra to Fort Garland, we proceeded thence subsequently up the Park to the Indian treaty on the Rio Grande; and from there _via_ Homan's Park and Poncho Pass north to Fair Play in South Park. These "parks," so called, are a peculiar feature of the Rocky Mountains and play an important part in the scenery. There are five of them--North, Middle, South, Homan's, and San Luis--of which we passed through the last three. They constitute in reality a great system of plateaus or valleys, morticed as it were into the very heart of the mountains, from twenty-five to fifty miles long by half as many wide, disconnected by intervening ranges, yet all alike in their general features. One of the main ranges of the Rocky Mountains bounds them on the east; but _the_ main range, the real Sierra Nevada or Mother Range--the great Snowy Range or real water-shed of the continent, dividing the waters of the Pacific from those of the Atlantic--runs along the west. True, this is disputed by enthusiastic Coloradoans; but the facts seem nevertheless, as above. The North Platte, South Platte, Arkansas, and Rio Grande, all take their rise there, and piercing the eastern range flow thence to the Atlantic or the Gulf, while no considerable stream flows thence to the Pacific. Kit Carson, whom we met at Fort Garland, the best geographer of that region, took this view of the subject, and I humbly concur. The largest of these Parks, by far, is the San Luis, and we found it fairly gridironed with trout streams, and rimmed around with mountains. Its general elevation is from six to seven thousand feet above the sea, with its surrounding peaks and ridges about as much more, which is too cold for Indian corn, though the other cereals--such as wheat, barley, oats, etc.--may readily be grown there. Volcanic agencies have had much to do with its formation, as its wide-spread igneous rocks and pebbles still plainly show. Along the Rio Grande and its numerous affluents wide bottoms have been formed, that are very rich--the very washings of the mountains; but elsewhere you have only rocks and gravel, sage-brush and grease-wood. It contains no timber, except a fringe of cottonwoods and poplars along most of the larger streams; but cedar, pine, and fir are found in the neighboring cañons and mountains. Cattle and other live-stock find good grazing in summer along the streams, and in winter they were said to thrive well on the coarse bunch-grass, with which the surrounding cañons all abound. The broad bottoms of the Rio Grande, waving with tall grass and fatter than the prairies of Illinois, ought to make magnificent meadows, and will some day when more of our Anglo-Saxon population overflows there. The population of the Park was grouped mainly in two or three Mexican hamlets, and was computed by Kit Carson (then Colonel of New Mexico Volunteers and Post Commandant at Fort Garland) at about five or six thousand only.