504 Notices of Memoirs—J. Lomas— 
NOTICHS OF MBEMOTRS. 
Desert ConpiTrions AND THE ORIGINeoF THE BritisH Trras.! 
By J. Lomas, A.R.C.S., F.G.S. 
(Concluded from the November Number, page 514.) 
HE occurrence of salt lakes in deserts is of the greatest interest 
and importance in the quest we have set before us. They are so 
characteristic of arid regions that it is essential we should have a clear 
impression of their peculiarities if we wish to make a true comparison 
with the rocks of the Trias. They have been described so frequently 
by travellers that I need only quote one or two examples. 
Munzinger,? in the “Narrative of a Journey through the Afar 
Country,” describes the great salt basin to the east of the Abyssinian 
mountains as bordered with walls of gypsum. Further he writes: 
‘‘ The first part of the salt basin is sandy, but after a short distance 
clay appears on the top, and every now and then we found a rain- 
ditch with powdered salt in it. After 14 hours march we found 
a line of potasse trees, otherwise no tree or bush. The soil by 
degrees becomes of a greyish tint, and further on resembles a frosted 
ploughed field; but at the end the bed of salt becomes more thick and 
hard and presents the appearance of a lake frozen over.” 
Captain C. G. Rawling,? in exploring Central Tibet, visited 
numerous salt lakes. Of Gore Tso he writes: ‘‘A fine lake was 
seen two miles to the east, but mounds of some white mineral, piled 
up along the banks, almost certainly indicated that the water was 
undrinkable. Although this was the 5th of July, the lake was frozen 
from end to end. . . . On the following morning I made my 
way to the shores of the lake and found . . . all around rose 
a solid ridge of salt deposit, three to four feet high and from thirty to 
forty feet wide. No vegetation grew within 500 yards of the shores, 
while to the north a barren plain stretched away for many miles. 
The lake is about 20 square miles in area.” 
Sven Hedin, writing of the Takla Makan desert, states that the 
dunes are arranged in a sort of network pattern with hollows—or 
bayirs—inside the meshes. Clay rises as oblong terraces or steps 
four to five feet high along the slopes, giving the appearance of beach 
lines. The bottom of the bayir is covered with a granular hard 
incrustation of salt, at a distance resembling rime. Upon digging 
eight or nine inches a thick deposit of pure salt is reached, evidently 
filling the bed of a desiccated salt lake, the margins and side terraces 
of which are coated with perfectly horizontal layers of yellowish-red 
clay eight to nine inches thick and hard as stone. In some bayirs 
a part remains moist, and is edged all round with a narrow belt of salt. 
A bed of gypsum was observed in some cases, and one contained the 
skeleton of a water bird and a dead:day-fly. 
1 Proc. Liverpool Geol. Soc., vol. x, pt. 3, 1907, pp. 172-180; slightly abridged. 
2 Geog. Journal, 1869, p. 200. 
8 «<The Great Plateau,”’ p. 61. 
