The province of _Burgos_ overlaps the plateau, and in its northern and southern extremities embraces the valleys both of the Ebro and the Douro, with their respective towns, Miranda del Ebro and Aranda del Douro. The basins of these two rivers are separated by the Oca or Idubeda mountains, which cross the centre of the province. The difference of the elevation of the two valleys may be seen in the fact that while Miranda del Ebro is 1600 feet above the sea-level, Burgos is more than 2800. Burgos (29,000) and Aranda del Douro were formerly towns of considerable commerce, and the former had at one time a claim to be considered the chief city of Northern Spain. It has now greatly fallen, but will always be visited for the noble remains of Gothic architecture in the city and its suburbs. Miranda del Ebro (3000), when the river formed the customs line for all commerce passing from the Basque Provinces into Spain, was of great consequence, and is now the point of junction for the northern lines of railway from Bilbao and from Irun. In this province, too, is the pass of Pancorbo, through which both road and railway wind; for savage wildness it is inferior only to that of the above-mentioned Despena-perros in the Sierra Morena. The whole province of _Logrono_ lies in the southern half of the valley of the Ebro, and leans against the mountains which form the supports of the great plateau. The Ebro forms its northern boundary, and its chief towns, Logrono (12,000) and Calahorra (7000), are both on the river. Here the traveller from the north first sees the Noria or Moorish water-wheel at work. The province is noted chiefly for its strong, rough wines, and for its agricultural products. Navarete is known in English history as the spot where the Black Prince and Bertrand du Guesclin fought out their mightiest duel, the one as the partisan of Pedro the Cruel, and the other of Henry of Trastamare.