Tertiary basic lavas cover large areas (e.g. El Leja) E. of Gali lee. These rocks are able to retain the rain and, when decomposed, form excellent soils for cereal growing and have been cornlands from early times. Small patches of volcanic material occur in Moab and also west of Jordan, especially near the Sea of Galilee. The drainage system on the plateau is peculiar. Its long and gradually rising western slope carries the main streams that eat back deep channels in the limestone before falling on the western plain. The eastern limit of the plateau falls precipitously into Jordan, and is cut deeply by periodic torrents that rush down its slope. So sharp is this eastern edge that Bethlehem, only 14 m. from the Dead sea, stands 3,842 ft. above its waters and 5,15o ft. above its deepest point.
Palestine divides itself naturally into two longitudinal strips— the maritime plain and the mountain region.
The slopes down to the coastal plain grew fruits and corn, and were the centre of agricultural life. Here blossomed the "Roses of Sharon." Israel's hold upon the plain was usually weak, and the south-west was the centre of the Philistine power. Any settlement on this plain was essentially a station along the great route between Egypt and the Hittites, Damascus or Assyria. As the Jewish Prophets foresaw, no power could ever maintain itself in such a position, and although the Philistines at one time had control of the foothills they were driven back by David and Solomon, and in the days of the Maccabees the Philistine power was no longer a distinct unit.
On the west side of the watershed the mountainous district extends about half-way to the sea, broken by deep valleys and passes. Among these the most important are the Wadi Selman (Valley of Aijalon), which seems to have been the principal route to Jerusalem in ancient times; the Wadi Ismain, south of this, along which runs a road from Jaffa to Jerusalem; and the Wadi es-Surar, a higher section of the bed of the Nahr Rubin, with its railway line. It was among these hills in early times, cut off from the great trade-routes of the plain, that the shepherds treasured their nomad traditions and preserved the old rites of worship of Jehovah as well as on the high places (Hebron, Bethel, etc.). Jerusalem was a holy city before it fell to David.
Between the mountainous country of Judaea and the maritime plain is an undulating region anciently known as the Shephelah. It is composed of horizontal strata of limestone, forming groups of hills intersected by a network of small and fertile valleys. In this region, which is of great historical importance, are the remains of many ancient cities.
On the east side of the watershed the ground slopes rapidly from its height of 2,500 f t. above sea-level to a maximum depth of 1,300 ft. below sea-level, within a distance of about 20 miles. It is a waste, destitute of water and with but scanty vegetation. It has never been brought into cultivation; but in the first Christian centuries the caves in its valleys were the chosen refuge of Christian monasticism. It descends to the level of the Ghor by terraces, deeply cut through by profound ravines such as the Wadi es-Suweinit, Wadi Kelt, Wadi ed-Dabr, Wadi en-Nar (Kedron) and Wadi el `Areijeh.