Page:An Introduction to the Survey of Western Palestine.djvu/191

175 PART IY. THE HIGHLANDS OF WESTEKN PALESTINE.

The Streams or Watercourses, together with the Water- partings of a country, form the primary foundation of its delineation, and the proper basis of its study. The Plains require the next consideration, for they form the threshold of the mountains, and often determine their limits. The intricacies of the relief, and the complicated forms of the Elevated Ground, are thus be'sieged by regular approaches, leading up to and denning the base of the outer walls, and penetrating the interior by exact drainage lines, which, in order to ! fulfil their functions, should not only define hori- zontal direction, but should also express by altitude, the vertical changes which they undergo.

The next step is the elimination from the highland mass of its Culminating Summits and the Ranges which are crowned by them. It is necessary to consider not only those ranges which form waterpartings, but also those which are intersected by rivers and watercourses, and make the edges of plateaus, often indeed, displaying a regularity, an altitude, and important consequences to nature, and par- ticularly to mankind, transcending in effect the waterparting ranges.

To eliminate from the tangled maze of the western high- lands of Palestine, the main ranges and groups that form a key to the whole mass, is the object of the following notes.

The rivers which define the limits of the survey under review, are singularly adapted to palliate the disadvantage of