= 
But the formations pass over one to the other, and there 
are species common to several formations. A description of 
the individual formations such as has been given in the 
preceeding pages can therefore only present a schematic view 
of the vegetation. It may bring the physiognomy of the ve- 
getation more clearly before the reader if I reproduce here 
a series of descriptions from selected localities in the desert 
of Transcaspia. 
1. Sand-desert at Tasha-Kirr on the right bank of the 
Amu Darya. June 22"? 1899: 
The Sand-desert in this place stretches right down to 
the river with a high glissade slope, and that this condition 
has probably existed for a long time may be confirmed a 
little farther north where there is a long high cliff of sand- 
stone 8 to 10 metres high. This cliff consists of strata of 
conglomerate with much sand (the stones attain the size ofa 
bean). Peculiar forms of erosion are shown, low columns and 
pillars of sandstone crowned with larger masses, probably 
the remains ot more resistent strata which have protected 
the lower parts. 
The brown desert behind is very rugged, dune behind 
dune each with crescent-shaped concavities turned towards 
SE. Tamarisks grow on the dunes nearest the river-valley, 
sometimes up to the summits, the bushes being about 2 met- 
res high. Where the river has eroded the foot of the glissade 
so that the sand has fallen down, one sees the stems and 
long roots of the Tamarisks hanging on the slope. 
Farther into the desert, the fresh green colour of the 
Tamarisks is lacking, but many dead remains of old stems 
and branches were seen, probably Tamarix. This is a sombre, 
naked desert formed of large, crescent-shaped dunes. The 
larger plants stand hundreds of metres apart. The most com- 
mon is Aristida pennata. None of this plant was seen in the 
most exposed places, the tops of the dunes. Calligonum and 
Ammodendron on the contrary defy the most unfavourable 
conditions and thrive well. Calligonum-bushes were seen on 
the very tops of the downs, a height of about 2 metres, and 
there was also a small tree with a stem. Now and again a 
bush of Smirnowia turkestana was found, its large, vesicular 
