CHAP. XIII THE '' BEHEADING'' OF RIVERS 253 



been continued farther northward and westward than its 

 present mouth, and it seems natural to conclude that the 

 connection between the Jordan and the African river systems 

 was established by a river, which flowed from Palestine into the 

 Nile. Professor Hull ^ has not only accepted this view, but 

 endeavoured to show that the connection was established 

 along the course of the brook Kishon, for, near the head of 

 its valley, a pass only 300 feet in height leads over into the 

 Jordan basin. It is known that in Pliocene times the Jordan 

 valley was occupied by a deep fresh-water lake, and Professor 

 Hull suggests that the drainage from it escaped by this 

 " Esdraelon Gap " into the Levantine basin. 



There does not, however, appear to be any sufficient 

 evidence in support of this view. No traces of gravels or any 

 river deposits, such as would probably have been formed by 

 so large a river, have been found upon the pass. The theory 

 that the Jordan discharged by a river flowing along the valley 

 of the Jalud and over the Esdraelon Gap into the valley of the 

 Kishon, assumes that this gap was then but little higher than 

 it is to-day, and that immediately to the west the ground 

 sloped down toward the Mediterranean. But the whole 

 arrangement of the river system in the district renders it more 

 probable that the Esdraelon Gap was formed by a river flowing 

 eastward instead of westward, and that at the time of its 

 formation the Jordan valley was even more effectually separated 

 from the Mediterranean than it is at present. This gives a 

 very different origin for the Esdraelon Gap, which can best be ex- 

 plained by reference to a parallel case near London (see Fig. 14). 

 All travellers to Brighton may notice that on leaving Croydon 

 the railway gradually ascends the broad, dry " Golden Valley." 

 Six miles south of Croydon the railway passes through a 

 tunnel and emerges into a valley, which runs at right angles to 

 the former, and is occupied by a tributary of the Mole. Looking 

 backward, the Golden Valley is seen as a gap on the hill face 

 above. If the traveller has time to walk up to this, he may 

 find upon its floor some beds of gravel containing pebbles of a 

 rock (Lower Greensand Chert), derived from the hills to the 

 south. This material can only have been brought into its 



1 E. Hull, "On the Physical Conditions of the Mediterranean Basin," Trans. 

 Vict. Instit. 1895, 10 pp. 



