The deserts in North America are generally bordered by a climate type that is often considered as transitional between the deserts and the forests, that being the grassland. The grassland is a climate type that has hot and dry summers, with the temperatures going well up, and it has a relatively long drought. The winters are the total opposite, as they are very cold and humid. These climate conditions have created suitable circumstance for the development of the grasses, so they are the dominant plants, and they are the reason as to why this climate has its name. The grassland climate can be found in the interior of the continent, and it is mostly bordering the desert from the eastern and northern sides. Nowadays, the areas that have this climate, are heavily used for agriculture, as the soil in these areas is very deep and highly fertile.
The Cheyenne tribe established their nation in the land that now belongs to the state of Montana. Due to the information contained in the question, we know that horses played a valuable role in the life of Deleep's tribe. This was true because of the vast distances the Cheyenne had to cover. We also know that buffalo inhabited the same area as Deleep's tribe. The geographic location of the Cheyenne nation corresponds well with the range of the bison.