Roraima desconhecida

The author, a professor of the "Ecole des Hauts Études", of Paris, and of the "Faculdade Nacional de Filosofia" of Rio de Janeiro, gives a report of the two geomorphologic expeditions that he has undertaken for the "Instituto Nacional de Pesquisas da Amazônia", through the northeast of the Territory of Rio Branco, Brazil. The first expedition took place in 1954, and the second in 1955. The region explored is situated approximately between 3° 40' and 4° 40', north latitude, and 59° 30' and 61° 30', west longitude. This territory is bounded on the northeast by Venezuela, and, on the southeast, it reaches the British Guiana border. The zone thus delimited includes not only the southern end of the sandstone tableland located at south of Mt. Roraima, an extremely mountainous region, but also, to the south, plain situated at north of the characteristic elbows formed by the two rivers. Tucutu and Uraricuera, just before they join their waters to become the White River (Rio Branco). There, we can find the most important passageways through the mountains to Venezuela, on one border, and to the British Guiana, on the other. The author describes the physical features of the country and its structure. The research was planned having in view full application of the geomorphologic science. The first chapters refer to the organizations of the expeditions and to his plans of work. This is followed by a report of essential scientific results. Finally, the connections of the physical background and the natural resources with the possibilities of their utilization are studied. aiming at orienting the colonization and the communication plans.