Burton's topographical descriptions are fuller, and his march to Mecca from Medina by the eastern route led him over ground not traversed by any other explorer in Hejaz: this route leads at first south-east from Medina, and then south across the lava beds of the Harra, keeping throughout its length on the high plateau which forms the borderland between Hejaz and Nejd.
Its general slope is to the north-east from the volcanic plateau of the Harra south of J.
These tracts are known as harra; the most remarkable is the Harrat El Awerid, west of the Haj route from Tebuk to El Ala, a mountain mass 100 m.
The harra east of Khaibar is also of considerable extent, and the same formation is found all along the Hejaz border from Medina to the Jebel el Kura, east of Mecca.
The surface of the harra is extremely broken, forming a labyrinth of lava crags and blocks of every size; the whole region is sterile and almost waterless, and compared with the Nafud it produces little vegetation; but it is resorted to by the Bedouin in the spring and summer months when the air is always fresh and cool.
Lying on the western slope of the peninsula, where that He slope is at its widest, between the Harra and the Red Sea.
Both are generally bare and unproductive, the uplands, however, contain the fertile valleys of Khaibar and Medina, draining to the Wadi Hamd, the principal river system of western Arabia; and the Wadi Jadid or Es Safra, rising in the Harra between Medina and Es Safina, which contain several settlements, of which the principal produce is dates.
Khaibar harra, runs north-eastward across the whole width of Nejd, till it is lost in the sands of the eastern Nafud, north of Aneza.
Arabian manuscripts describe an eruption on the harra near Medina in A.D.
Snow falls on the Harra and on the Tehama range in northern Arabia, and Nolde records a fall of snow which lay on the Nafud on the 1st of February 1893.
- nfäscus Ng, a -?; reat Scale, I:13,000,000 Railways Principal Capitals (States and larger Provinces) Capitals of smaller Provinces Governorships, Districts Sic aana Beds (Harra,) Deserts......
It is said that a thousand bastards (the "children of the Harra") were born in consequence of these days.