As one emerges from the jungle, which covers the eastern slopes of these mountains, and looks down over the province of Abra, he sees an exceedingly broken land (Plates I and II), the subordinate ranges succeeding one another like the waves of the sea. The first impression is one of barrenness. The forest vanishes, and in its place are long grassy slopes, broken here and there by scattered pines and lower down by dense growths of the graceful, feathery bamboo. But this lack of trees is more fancied than real, for as one proceeds down any of the valleys he meets with side canyons, where the tropical jungle still holds sway, while many a mountain side is covered with a dense undergrowth of shrubs, plants, and vines. It seems probable that the forest once covered the western slopes of the mountains, but accident and intention on the part of man has cleared broad sections. As soon as the shade is removed, the land is invaded by a coarse grass (the _cogon_), and this is burned over each year in order to provide feed for the stock and to make good hunting grounds. The young trees are killed off and reforesting prevented. Numerous streams plunge from the high mountains toward the coast. In places they rush through deep gorges between high mountains, again they pass peacefully through mountain valleys. Everywhere they are fed by minor streams and waterfalls until at last, as they emerge into the broader valleys of the Abra and its tributaries, they are rivers of respectable size. The great central valley of Abra is far from being a level plain. In places, as about Manabo, Bukay, and Bangued, there are stretches of level land; but, for the most part, the country is rough and broken. This valley is cut off from the sea by the Coast Range of mountains which forms the provincial line between Abra and Ilocos Sur, while another heavy spur forms the northern limits of Abra from Ilocos Sur to the Cordillera Central. Two small and rather difficult passes afford entrance from the coastal plain into the valley, but the chief avenue of communication is the cut through which the Abra river reaches the sea. So narrow is this entrance that, at high water, the river completely covers the floor and often raises its waters ten or fifteen feet up the canyon side. In recent years a road has been cut in the rocks above the flood waters, but even to-day most of the traffic between Abra and the coast is carried on by means of rafts which are poled up the river. [7] The rainfall averages about one hundred inches, and most of this precipitation takes place between May and the end of September. This, coupled with the lack of forest, causes the rivers to become rushing torrents during the rainy season, while during the balance of the year most of them are mere rivulets. Under these conditions there has been no development of navigation by the mountaineers. On occasion they may construct a bamboo raft, but they possess no boats of any description.