96 REPORT—1852. 
the Red Sea. The actual condition of this strait, Tirahn, would give countenance 
to the idea, that it is in process of closing; for by the chart it will be found that 
a well-defined bank or shoal is advancing from the nearest opposite points, between 
which the channel is unfathomable and is less than half a mile wide. 
The growth of coral reefs*, deposits of sand and grayel, &c., cast up by the sea, 
may have, in the same way, closed up the hypothetical strait at Akabah, and cut off 
the communication between the two gulfs¢. Then the upper basin being of great 
extent, evaporation from its surface would exceed the supplies poured into it from 
the river Jordan, and other small streams, and would therefore cause it to fall, as 
well as to contract its limits. 
If this effect of evaporation had not been modified by other circumstances, it would 
have left the whole dry bed of the basin with a uniform covering of alluvial deposit. 
But the lines of silt seen at different elevations, the terraces, the sand-cliffs, the 
flat-topped hills and the parallel beaches, concur in showing that the subsidence of 
the surface was not always gradual, but that it has been subject to occasional and 
sudden changes of level, of which these are the monumental records. ; 
On these assumptions, the lake Asphaltites in its original state was the upper end 
of a long and narrow arm of the ocean, extending from the base of Mount Hermon, 
or Anti-Libanus, nearly 2000 miles, and gradually increasing in breadth from a 
few yards at the north end to about 200 miles at the other extremity. 
The undulations in the bed of this fissure divided it by narrow straits into several 
basins. 
In the same way the upper basin, or the portion cut off from the Gulf of Akabah, 
would have had also its undulations in the bed, in other words, irregularities in 
depth. 
Mount Hermon. 
Level of the Mediterranean and of the Red Sea. 
Akabah, 
c a ae 
ao SS ee Ss » 

Wadi Arabah. 


Valley of the Jordan. 
a. Lake Tiberias, b, 6, b. Barrier. ce. Dried-up Strait. 
1. First line. 2. Second line. 3. Third line. 
The prodigious evaporation from so large a surface would have brought it down, 
soon after the separation, from the upper line in the diagram, to the first irregularity 
or barrier on the second line; where the further process of evaporation would cause 
a division of the waters into two basins, of which the upper, having the Jordan run- 
ning through it, would preserve for a time its level at the second line, while the» 
lower basin, being still so much larger in proportion to the supply, would continue 
to fall. 
Suppose it to have fallen to the third line; and then, the upper basin beirg still 
at the level of the second line, if the weight of water, or the action of the current of 
the Jordan on a soft bed, or their combined effect, forced the barrier, the water of 
the upper would have been transferred to the lower basin, with a violence that would 
have torn up and scoured the sides of its former bed, leaving marks of its action in 
rugged ravines, and traces of its ancient level round the margin. 
But if the lower strata of the barrier had been of rock so solid as to resist the 
action of the waters at a certain point, then a part of them would have been retained 
in the depression, forming a freshwater lake, as the lake Tiberias. 
The process would have been repeated, dividing at the barriers, or shallowest 
parts, successively, which having also been forced by the same action, the same 
effects would be produced by the violently retreating waters, leaving vestiges, such 
as the monticules or conical hills, with their crowning attestations of former levels, 
the sand cliffs of the banks of the Jordan, and the more recently formed parallel 
beaches near the Dead Sea. 
As the only solid barrier was at the lower end of the lake Tiberias, this is the only 
* See Riippell. + Or the separation might have been caused by a slight upheaving 
of the land by volcanic agency. 
