654 GLACIER-EROSION THEORY 



quently found running nearly parallel to the general axis of elevation.' 

 2. Transverse valleys. — ' Deep valleys are sometimes found of which 

 the directions are nearly at right angles to that of the general eleva- 

 tion.' He admits that these latter may frequently be due to the effects 

 of erosion, but states that in some instances they appear to have 

 been obviously formed by the elevation of the strata on either side of 

 them ; and he cites a beautiful example of this kind of formation in a 

 river in Wales. So far as I am aware, no attempt has yet been made 

 to investigate how much of the expansion of a transverse valley near 

 the axis of a lofty chain like the Himalayan is due, theoretically, to a 

 fissure of upheavement, and how much to subsequent erosion. 



Suppose a given area of the bed of the ocean to be thus upheaved, so 

 as to elevate part of it, in the shape of islands, above the sea-level, and 

 leave part of it submerged, but with the dislocations and fractures and 

 fissures of both orders within the scour of tides and currents : the 

 abrading and solvent action of water, with other atmospheric agents, in 

 the former case, and the movements of the ocean in the latter, ope- 

 rating during long periods, will produce enormous alterations of the 

 exposed surfaces, denude, widen, and deepen the rents, fissures, and 

 other inequalities. Let the action of ice be superinduced, as exem- 

 plified on the shores of Spitzbergen, Smith's Sound, and the ancient 

 fiords of Norway, or upon mountain chains, the effects will then be 

 produced on a scale of very great magnitude. But the fractures, 

 fissures, foldings, and dislocations, and the uptilting of the beds caused 

 by the original movements of upheavement have determined the di- 

 rection in which the subsequent abrading and denuding causes have 

 operated. The same line of reasoning applies to the upheavement into 

 mountain chains of land already above the level of the sea. Some- 

 thing like the foregoing would embody the combined results of the 

 mechanical theory and empirical reasoning. — The Header, Feb. 27, 

 1864. 



The Valley of the Jordan, regarded as a whole, is one of the most re- 

 markable narrow rectilinear indentations of which physical geography has 

 taken cognizance as occurring on the surface of the earth : a deep trench 

 extending from the mouth of the Orontes at Antioch to the Gulf of 

 Akabah, and bounded on either side by considerable elevations, but 

 interrupted at two points — first, by Lebanon and Hermon, dividing the 

 watershed of the Orontes from that of the Jordan"; second, by the high 

 ground bounding the basin of the Dead Sea to the south. The trough 

 is thus divided into three segments, from north to south : 1st, in the 

 Valley of the Orontes; 2nd, the Ghor, or valley proper of the Jordan; 

 3rd, the Valley of Arabah. The second of these segments is that to 

 which attention is now called. The Jordan arises out of springs near 

 Hushbeyah, on the western flank of Mount Hermon, at an elevation of 

 about 1,700 feet above the level of the Mediterranean. After receiving 

 some affluents, it runs due south into the Lake of Merom (El Huleh), a 

 triangular basin about 4^ miles long by 3^ wide, and elevated about 

 50 feet above the level of the sea. The lake occupies the southern end 

 of an intramontane plain 15 miles long by 5 wide, indicating the former 

 boundaries of the sheet of water. From Lake Merom the river descends 

 by a contracted channel to plunge into the Lake of Tiberias, Avith a fall 

 of about 600 feet in a distance of 9 miles, being 66^ feet per mile. 



