Trans-Gambia Highway Trans-Gambia Highway The Trans-Gambia Highway is the most important road in The Gambia, running across the centre of the nation in a north-south direction. The road is also economically important for Senegal, in which it is designated as the N4 road. The Gambia is an elongated state forming a country that is almost surrounded by Senegal (but not an enclave, as it also borders the Atlantic Ocean). The Gambia almost separates the Casamance region from the remainder of Senegal. The Trans-Gambia Highway provides the most important connection between the two parts of Senegal. As the N4, it runs from Kaolack
Geology of Gambia Geology of Gambia The geology of Gambia is defined by thick and comparatively recent sequences of sediments and sedimentary rocks, deposited in the last 66 million years. The country is underlain almost entirely by geologically recent Cenozoic sedimentary rocks. Much deeper basement rocks are likely present, although they are not well understood. Most research has focused on oil and groundwater exploration. The oldest rock units recognized in the west of the country, along the Gambia River are sandstones and kaolinitic claystones from the Oligocene, Miocene or Pliocene. Ironstone, including iron oxides, gravel, clay and sand dating to the Pleistocene are