V. =Peculiarities.= The Edomites, though descended from the stock of Abraham, adopted the idolatry of the Canaanites, with whom they had intermarried. But their most remarkable feature, as a nation, was that of dwelling in caves. The mountains of Idumea are of soft sandstone, easily wrought, and are penetrated with caves and grottoes, which were used, not like those of other nations, for burial places, but for residence. The rock-hewn temples, palaces and homes of Petra, so well known to travelers, are magnificent in appearance. The custom probably arose from the fear of robbers, and from the ease with which the caves could be excavated in the sandstone rock. OUTLINE FOR REVIEW. 1. _Boundaries._ Moab; Desert: Midianites; Arabah. 2. _Names._ Seir, Edom, Idumea, Geballene, Jebal and esh Sherah. 3. _Natural Features._ Mountains; Soil; Capitals (Bozrah, Petra). 4. _History._ Horites; Esau; Edomites; Israelite Supremacy; Chaldeans; Nabatheans; Maccabeans; Romans. 5. _Peculiarities._ Religion; Rock Houses. THE WANDERING IN THE WILDERNESS. There are great difficulties in fixing the location of the places and the order of events in the history of the forty years which intervened between the exodus, or "going out," from Egypt, and the entrance into the Promised Land (B.C. 1250-1210). These difficulties arise from various causes: the antiquity of the events, the fragmentary character of the history, the extent of the country, our scanty knowledge of the region, and especially the changes which have taken place in the sea-coast during the 3,000 years past. While the general course of the journey can be easily defined, the particular localities are, in many instances, exceedingly uncertain. For the convenience of the student, we divide the entire journey from Egypt to Canaan into sections.