278 THE BASIN OF EASTERN PERSIA AND SISTAN. 
plain and the swamp are absent, and the lake at high water meets the gravel desert. 
In approaching Sistan on this side by the ordinary ronte from the northwest, the 
traveler mnst pass throngh the Gate of Rendan, a gorge cut across a low ridge of 
limestone. The bottom of the gorge is filled with fine alluvium, chieflj- silt, which 
is rapidly being cut away by the stream (cf. the Kanab canyon in Utah, ante p. 272). 
The latter luis intrenched itself to a depth of 20 feet. This gate is remarkable for 
its large grove of date palms, which flourish here in the shelter of the mountains, 
although alsewhere in Sistan the violent wind prevents their growth. 
Soutluvest of Bendan the alluvium of the gorge broadens into the gravel-covered 
desert of Sistan. As far as the eye can reach it encounters a smooth expanse of 
small dark pebbles, clean swept by the wind, and devoid of vegetation except for a 
small bunchy weed every two or three hundred feet (fig. 164). Valleys are incised in 
this plain, but are so sharply depressed as not to break the lifeless monotony of the 
^Tavel, which is only interrupted by islands of buried mountains. The valleys are 
Fig. 164. — A Typical Portion of ihe Gravel Desert northeast o( Sistan. 
universally terraced. Along the Bendan stream a second terrace soon develops 
below that at the gate. These two continue to the mouth of the valley, varying in 
height, but very persistent. In many places a third small terrace appears below 
these, but it is not persistent. All along the west shore of the lake the same thing 
seems to be true ; the main streams are bordered b}' two good terraces and there 
are traces of a third. In the side valleys the two lower terraces soon disappear. 
East of Bendan the gra\'el desert suddenly comes to an end in the steep bluffs 
which border the lake on the northwest. At Bereng, where the road to Sistan 
crosses the " hamun " (swamp) the bluffs are only 20 or 30 feet high, and stand 
somewhat back from the water. Farther north, however, they approach the water 
until they are undercut by it and fonn almost perpendicular cliffs 100 feet high. 
Still farther north, near Kharikha and Kuh-i-Chaku, the total height of the bluflfe 
becomes 300 or 400 feet, although the)- stand farther from the lake and are not 
to-day being undercut. Just how far these bluffs e.xtend is not known. I followed 
them for 40 miles from Bereng to the northwest corner of the lake, and saw them 
