Major ethnic groups include the Fulbe (Fula), who are Islamic pastoralists, and numerous Muslim and animist speakers of Adamawa, Chadic, and Nilo-Saharan languages. French is the language of education, though Fulfulde, the Fulbe language, is widespread as a lingua franca. In 2008, the President of the Republic of Cameroon, President Paul Biya signed decrees abolishing "Provinces" and replacing them with "Regions". Hence, all of the country's ten provinces are now known as Regions. Bands of alternating metamorphic and sedimentary rock interspersed with granite characterise the north's geology. Granite covered in volcanic basalt makes up the southernmost reaches, which form part of the Adamawa Plateau. A series of faults lies north of this and separate the plateau from the band of metamorphic stone to its north. Random granite deposits also characterise this area. The Mayo Rey and Vina River cut north of this portion, leaving deposits of sedimentary stone except in the granite east. North of this lies a band of sedimentary alluvium, clay, limestone, and sandstone. Faults tentatively follow the BÃ©nouÃ© River north of this and form a barrier to split the remainder of the province, with metamorphic rocks such as gneiss, mica, and schists dominating to the south and sedimentary stone making up the north. Another large band of metamorphic rock makes up the territory northwest of the BÃ©nouÃ© basin. The Mandara Mountains, which run roughly north-south at the province's Nigerian border, are irregular in that they are volcanic, composed mostly of crystalline and metamorphic rock and granite.