The hills back of Santiago Bay, separating it from the Valley of the Cauto, are similar in structure to the northern foothills of the main sierra. In the western part of the range, the mountains rise abruptly from the depths of the Caribbean Sea, but near the City of Santiago, and to the eastward, they are separated from the ocean by a narrow coastal plain, very much dissected. The streams which traverse it occupy valleys several hundred feet in depth, while the remnants of the plateau appear in the tops of the hills. East of Guantanamo Bay there are mountains which are structurally distinct from the Sierra Maestra, and these continue to Cape Maysi, the eastern terminus of Cuba. To the west they rise abruptly from the ocean bed, but further east they are bordered by terraced foothills. Towards the north they continue straight across the island as features of bold relief, connecting with the rugged Cuchillas of Baracoa, and with "El Yunque" lying to the southwest. Extending west from this eastern mass are high plateaus and mesas that form the northern side of the great amphitheatre which drains into Guantanamo Bay. Much of this section, when raised from the sea, was probably a great elevated plain, cut up and eroded through the ages since the seismic uplift that caused its birth. The most prominent feature of the northern mountains of Oriente Province, west of "El Yunque," is the range comprising the Sierras Cristal and Nipe. These extend east and west, but are separated into several distinct masses by the Rio Sagua, and the Rio Mayari, which break through and empty into harbors on the north coast. The high country south of these ranges has the character of a deeply dissected plateau, the upper stratum of which is limestone. The character of the surface would indicate that nearly all the mountains of the eastern part of Oriente have been carved through erosion of centuries from a high plateau, the summits of which are found in "El Yunque" near Baracoa, and other flat topped mountains within the drainage basins of the Mayari and the Sagua rivers. The flat summits of the Sierra Nipe are probably remnants of the same great uplift. Below this level are other benches or broad plateaus, the two most prominent occurring respectively at 1,500 and 2,000 feet above sea level. The highest summits rise to an altitude of 2,800 or 3,000 feet. The 2,000 foot plateau of the Sierra Nipe alone includes an area estimated at not less than 40 square miles. It would seem that these elevated plateaus with their rich soils might be utilized for the production of wheat, and some of the northern fruits that require a cooler temperature than that found in other parts of Cuba.