TRANSACTIONS OF SECTION C. 363 
2. Note on the Occurrence of Loess-deposits in Egypt and its Bearing 
on Change of Climate in recent Geological Times.1 By H. T. 
Forrap, M.A., F.G.S. 
At a recent meeting of the Association Dr. Hume and Mr. Craig submitted 
the view that there had been no change, except that of gradual desiccation, in 
recent geological times in Egypt. Since their paper was published, evidence 
that the change of climate has not been uniform has been recorded from neigh- 
bouring countries. The following short paper is intended to show how eolian 
desertic deposits may be interstratified between freshwater beds without any 
change of climate. 
In the northern delta of Egypt are great stretches of flat land a few feet 
above sea-level. These areas are covered by ordinary Nile alluvium and 
remain damp during the winter months but dry in summer. Owing to the 
evaporation which takes place during the spring and early summer, soluble salts 
accumulate at or near the surface of the soil rendering it incoherent and 
powdery. Winds are now able to lift and transport this material until it is 
arrested by the roots of halophyte plants or other obstacles. Here also are 
deposited the dead shells of helices, and occasionally also the remains of land 
animals, such as the jackal, rat, bird, lizard, or snake, which have been seen 
frequenting dust-dune areas. In fact, the dust dunes of northern Egypt, known 
as Kardud to the inhabitants, are local deposits of Loess. 
A depression of the land of only a few feet, and such as that which has 
taken place since Roman times in Egypt, would cause another fluviatile layer 
containing the common shell Cyrena fluminalis or a lacustrine bed to be 
superimposed upon them. It is thus manifest that a desertic deposit inter- 
nee between two freshwater beds is not necessarily a proof of change of 
climate. 
3. Discussion on the Physiography of Arid Lands. 
Introduction. By Professor Sw T. H. Houuanp, K.C.1.H., D.Sc., 
F.RLS. 
The principal defect in published accounts of the physiography of arid lands 
is due to the absence of data showing the amount as well as the kind of 
physical changes in progress. This deficiency is to be expected. Few qualified 
observers are able to study arid lands for long continuous periods; such regions 
are thinly populated, and, from an economic point of view, their problems are 
of relatively small importance. It is not surprising, therefore, that, while 
we have abundant illustrations—pictorial and literary—regarding the nature of 
geological phenomena in the desert, we are only to a limited extent able to 
substantiate by trustworthy figures our general conclusions regarding the rates 
of destruction, transportation, and reproduction of desert formations. 
The investigation made during the years 1903-08 of the salt resources of the 
Rajputana desert was undertaken on behalf of the Government of India with 
a definite economic object in view, and the opportunity was turned to account 
to make a quantitative test of one phase of desert phenomena—namely, the 
zolian transportation of salt in the form of fine dust.? 
There are several intermittent saline lakes lying in depressions on the sand- 
covered highlands of Rajputana. In one case—namely, the Sambhar Lake—the 
underlying silt, tested to a depth of tweive feet over an area of 68 square miles, 
was found to contain some fifty-five million tons of sodium chloride. The 
quantities of salt so stored are altogether in excess of the amount that could be 
accumulated by normal fresh-water rivers acting within any reasonable geological 
period under present physiographic conditions. There are no rock-salt deposits 
known within the region under consideration, and the underlying rocks are 
Archean gneisses and schists covered with a thin mantle of sand. 
1 By permission of the Director-General of the Egyptian Survey Department. 
* For details see T. H. Holland: successive Annual Reports of the Geo- 
logical Survey of India published in Records G.S.Z. during 1904-09. 
