394 TI. 0. Russell—The Jordan-Arabah and the Dead Sea. 
It, has been concluded by those most familiar with the Dead Sea 
basin, that the ancient lakes which occupied it did not overflow. 
This conclusion is based on the fact that the highest terrace observed 
and the highest exposures of lacustrine sediments that have been noted, 
are several hundred feet lower than the bottom of the pass leading to 
the Gulf of Akabah, which seems the most probable location of an 
ancient outlet if one existed. It is to be remembered in this connec- 
tion, however, that a special examination of the terraces in question 
has not been made, and from the reports published it is not evident 
that the highest water-record reported is the highest that exists. A 
critical examination of the pass mentioned above, in reference to the 
possible existence of a stream-cut channel across it, does not seem to 
have been made. If evidence of such a channel should be found, the 
occurrence of a wave-cut terrace at the same horizon on the borders 
of the basin to the north would be expected. 
Among the many observations desired of the explorer in Palestine 
and adjacent regions, we would suggest in addition to those already 
mentioned, a measurement of the rate of evaporation from the surface 
of the Dead Sea, and the rate of evaporation of fresh water under the 
same general conditions. Also, a study of the succession and character 
of the precipitates which would be obtained on evaporating the water 
of the Dead Sea. The influence on the character of the salts thus 
obtained, of changes of temperature similar to the annual variations 
which occur in Palestine, should likewise be considered. 
Similarity of the Dead Sea basin to the Great Basin in America. 
There are so many corresponding features between the structure, 
recent geological history, scenery and present climatic condition of 
the Dead Sea basin and the Great Basin in our own country, that I 
am tempted to compare the two in detail. Space will not admit, 
however, of more than a brief summary of their points of re- 
semblance. 
The Jordan-Arabah depression is an isolated example of a type 
of fault basin which has been repeated many times at about the 
same date, in the western part of the United States, where the 
“basin range structure” prevails. This structure in America was 
impressed on a region which previously drained to the ocean, thus 
presenting a sequence of events which seems to have had a parallel 
on a smaller scale in the Dead Sea basin. The depressions which ~ 
resulted from dislocation both in Asia Minor and in the Far West,! 
became the basins of large lakes during the Quaternary period. In 
the Great Basin some of the ancient lakes overflowed, others were 
not drained, and as in the case of the Dead Sea, became concentrated 
brines. The lakes in both instances were fresh during their greatest 
expansion, but became saline when concentrated. The lakes referred 
to in America had two high-water stages separated by a period of 
1 This convenient but indefinite term has come down to us from the time when the 
western part of the United States was but partially explored, and refers to the vast 
region west of the bold, eastern face of the Rocky Mountains. It is in this region, 
between the Rocky Mountains and the Sierra Nevada, that the area of interior 
drainage termed the Great Basin, mentioned several times in this paper, is situated. 
