The fourth principal mountain range of the Republic, the Neiba Range, is sometimes classed as a part of the Cordillera Central. It rises on the western bank of the Neiba River and runs west parallel with the central chain, into Haitian territory. Among its principal peaks is Mt. Panso, 6200 feet high. The fifth principal range, situated in the extreme southwest of the Republic, is known as the Baboruco Range, and sometimes as Maniel de los Negros. It begins at the Caribbean coast south of Barahona Bay and runs west into Haiti, forming an integral portion of the mountain chain that traverses the great peninsula in the south of the Republic of Haiti. These several ranges and their offshoots divide the country into a number of distinct regions, which, owing to the difficulty of communication, have developed more or less independently of one another. The most important division is that effected by the broad central belt of mountains which, twelve miles wide in its narrowest part, and extending from the shores of the Mona Channel to and beyond the Haitian frontier, constitutes a rugged barrier between the north and the south of the Republic. The district to the north of the Central Cordillera, comprising the richest portion of the country, still retains its old Indian name "Cibao"--a word which awoke fond hopes in the heart of Columbus who identified it with "Cipango," the Japan he was so eagerly seeking. The Cibao includes the northern slope of the central range with the fertile valleys enclosed by branches of that range, the Samana peninsula, the Monte Cristi Range with its valleys and coastal plains, and particularly the magnificent valley of the Cibao, which lying between the central chain and the Monte Cristi Range, extends all the way from Samana Bay to Manzanillo Bay. The length of this remarkable valley is about 150 miles, its average breadth is 10 miles in the northwestern and 15 miles in the southeastern part, and it comprises the most fertile lands and the most populous interior towns of the Republic. The highest part of the valley is about 600 feet above sea-level and is situated at its middle point, near the city of Santiago, where a line of low hills dividing the valley into two parts forms a watershed for its rivers. The northwestern of these two sections is known as the Santiago or Yaque valley and forms the greater portion of the basin of the Yaque del Norte, while the southeastern half, through which the Yuna River flows, is the superb Royal Valley or Royal Plain.