We can thus, in some degree, picture to ourselves the Scotland of this period. Instead of the large tracts of cultivated land and the modern mansions of its possessors surrounded by plantations, we should see forests of trees of native growth, from amid which, or on their margin, would rise the towers of the royal castles, or those of the Norman barons. We should see small patches of cultivated land, interspersed with long stretches of barren heath. In sheltered valleys we should find the seats of the early bishoprics of the Celtic Church, and the more imposing monasteries of the regular clergy and monastic orders subsequently introduced, surrounded by a greater extent of cultivated land, and with the huts of the occupiers of the soil clustering round. On the banks of the navigable rivers, or at their mouth, we should find settlements of the trading and industrial population protected by rude walls; and we should find the northern and western districts exhibiting very much the same characteristics as they did during the succeeding centuries:—the two great leading mountain chains of the Mounth and Drumalban forming a succession of hunting-grounds or forests, left to the red-deer and other game; the minor chains leading from them to the south-east and north-east terminating abruptly on the lowland plains, and forming a great mountain barrier, extending on the south in an oblique line from Ben Lomond to the great range of the Mounth near Stonehaven, and on the north from the same range at Ballater to the river Nairn, through which the great rivers rising among the western hills pour their waters, through narrow gorges which form the passes into the mountain region. Within this line the country would be mainly used for pasturage, and its natural defences would render but few artificial fortifications necessary. [Sidenote: Population of Scotland in the reign of Alexander the Third composed of six races.]