— 116 — 
pseudophragmites, Hippophaës, Inula ammophila, Salsola Kali 
and Cirsium arvense were likewise seen. 
The characteristic feature of Tamarisk-dunes is the fact 
that the sand lies in strata. These are about 2 cm thick and 
separated by dark layers of dead, half-disintegrated inflo- 
rescence-axes, flowers and other deciduous parts of the Tama- 
risk (sticks etc.) These layers are further divided into layers 
parallel with the thicker layers, but here no dark stripes 
intervene. 
The dunes were completely rounded off on the top and 
covered by fine, constantly drifting sand. 
How have these stratified Tamarisk-dunes been formed? 
The expedition found similar dunes in the lowlands of Trans- 
caspia (PAULSEN, 1912, p. 96), which are described as “Tama- 
risk-knolls” and we read, — “they are presumbably remains 
of a former continuous tract of a sandy soil now blown away 
except where the roots and shoots of the Tamarisks have 
kept the sand at the old level. Mac Doucaz has pictured 
sand-knolls formed in the same way by a Rhus-species.” 
It is possible that the Tamarisk-dunes of Wakhan have 
been formed in the same manner, but it is more probable 
that they have been formed free and that their growth con- 
tinues, until they are finally blown out; for on our return to 
Wakhan in the winter (March), we revisited the Tamarisk- 
dunes examined in September, and which at that time had 
pure sandy surfaces, and found them covered with fallen 
twigs and inflorescence-axes. 
It was impossible to tell the origin of the fine stripes in 
the strata. It may be that on calm days the sand is puttied 
fast (with rain?) and that every additional drift of sand con- 
tributes a layer (stripe). 
Cultivated land i Wakhan lies on the terraces above 
the river as was stated above. It is irrigated by means of 
the brooks streaming down the mountain-sides. The me- 
thod is as follows. From the point at which the brook flows 
out on to the terrace, a main canal with a slight fall is con- 
ducted above the town and its fields. From this main con- 
