The Oyapok, or Vicente Pinzon, is the best-known of the group and forms the boundary line between Brazil and French Guiana under the arbitration award of 1900.
The boundary line follows the crest of the principal chain or ridge (Riesenkamm), which stretches along the northern side of the group, with an average height of over 4000 ft.
The main range of the Rockies follows the boundary line between Montana and Idaho west and north-west from Yellowstone Park in Wyoming to Ravalli county, then turns eastnorth-east to Lewis and Clark county, and from there extends' north-north-west into Canada.
The principal rivers of this region are Sama (which forms the provisional boundary line with Peru), Tacna, Camarones, Loa, Copiapo, Huasco, Elqui, Limari and Choapa.
In 1905 Liberia proposed to France that the boundary line should follow the river Moa from the British frontier of Sierra Leone up stream to near the source of the Moa (or Makona), and that from this point the boundary should run eastwards along the line of water-parting between the system of the Niger on the north and that of the coast rivers (Moa, Lofa, St Paul's) on the south, until the 8th degree of N.
All western trade in Canada of the vast provinces of Manitoba, Saskatchewan, Alberta and British Columbia, must pass through the narrow belt of loo m., lying between the international boundary line and Lake Winnipeg.
It soon after becomes the boundary line between the departments of Cher and Nievre, and reaches the Loire 4 m.
The finest examples of this kind are the moraines about Jackson Lake on the basin floor east of the Teton Range (Grand Teton, 13,747 ft.), a superb north-south range which lies close to the meridional boundary line between Wyoming and Idaho.
The Trans-Andine territory occupied by Ecuador is a wedge-shaped area between the Coca and Napo, the provisional boundary line with Colombia, and a line running nearly west-south-west from Huiririma-chico (about lat.
Its northern boundary is, for the most part, formed by Lake Ontario and the St Lawrence river, which separate it from the province of Ontario, Canada; but north of the Adirondacks the boundary line leaves the St Lawrence, extending in a due east direction to the lower end of Lake Champlain.