THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE V. VOL. I. 



No. XIL— DECEMBER, 1904. 



L — The Kishon and Jordan Valleys. 

 By Professor T. G. Bonney, D.Sc, LL.D., F.E.S. 



THAT broad trench tbrougla the Palestine Highlands, an ancient 

 highway and battlefield of nations — the plain of Esdraelon or 

 the valley of Megiddo, together with the plain of Acre — has for 

 long presented to me a difficult problem in Physical Geology, 

 for it seemed inexplicable by subaerial denudation under existing 

 conditions. Its floor varies roughly from five to eight miles in 

 breadth ; running approximately from south-east to north-west, 

 it is bounded on the more western side by the limestone mountains 

 of Samaria and on the more eastern by those of Galilee. The former 

 descend from the ridge of Carmel (1,742 feet at highest) with 

 a fairly steep escarpment, which becomes a little less regular as we 

 follow it to the bastion-mass of Mount Gilboa ; the latter correspond 

 in their general outlines with those of the eastern portion of Samaria, 

 but the advance of a lower spur towards the south-west divides 

 the plain of Esdraelon from that of Acre, by a kind of strait in 

 which, so far as I could see, there is but little level ground on either 

 side of the Kishon. This spur, however, of the northern hills, 

 hardly does more than interrupt the floor of the Kishon valley, for 

 above it the great trench is continued between two hill masses, 

 much of these ranging from thirteen to sixteen hundred feet above 

 sea-level. Beyond the strait the upper basin (plain of Esdraelon) 

 quickly broadens out, extending towards the south-east for about 

 fifteen or sixteen miles, where it is divided into two arms by Jebel 

 Duhy (Little Hermon) (1,690 feet), which is thus isolated from 

 Tabor (1,846 feet) on the north, and from Gilboa (1,698 feet) on the 

 south : a broad, rather shallow, grassy valley descending from the 

 last-named mass to lose itself in the plain, Neither it nor one 

 or two other tributaries from the Galilee hills count for much, but 

 the two arms maintain their trench-like form, cutting through the 

 limestone isthmus which must once have united Samaria and 

 Galilee. These are still, though much narrower than the plain 

 of Esdraelon, disproportionately broad ; their watersheds are low, 



DECADE v.— VOL. I. — NO. XII. 34 



