Arabia, Najd

The western part of Najd (Nejd, meaning �Highland�), known as Upper Najd, lies within the Arabian shield with an average elevation of 4,000 feet; the eastern part falls within the sedimentary province with the city of Riyadh (Ar-Riyad), near the eastern edge, having an elevation of about 1,950 feet. The principal drainage of Najd consists of a number of eastward-flowing wadi systems that