GEOLOGICAL HISTORY OF NORTHEASTERN PERSIA. 243 
The Jatn Basin. — ^The deposits of the Jam basin south of Zorabad are disclosed 
in a number of terraces along the Heri Rud and its tributaries. They consist of fine- 
grained brown silts, neither sand nor clay, but between the two. Most of the 
silts are reddish-brown in color, others are brown, brownish-purple, or green. 
They contain gypsnm in thin and verj' pure transparent layers, which are some- 
times so abundant that the ground is white with fragments. Often the strata lie 
horizontal, but there are many places where warping has taken place. For instance, 
south of Danidue a terrace 180 feet high consists of a cap of coarse slaty gravel 
lying unconformably on silts dipping 6° N. The edges of the Jam basin were not 
seen, and we can not be sure whether the amount of warping increases from the 
center outward. 
An interesting point in regard to the Jam deposits is that as a whole they much 
resemble the Moencopie beds which occupy so large an area in the plateau region 
of the United States (Goldthwait, pp. 203, 205, 210). Not only is the general 
character of the two formations similar, but the brilliant color and peculiar fonn 
of the cliffs are strikingly alike, while in each case a gravel cap protects the soft 
underlying silts. Even the ten-aces present the same appearance, although those of 
America are structural, while those of Persia are fluviatile. 
The Ncmcksar Basin. — In the Nemeksar basin, 75 miles south of the Jam River, 
many of the phenomena of the Jam basin are repeated. The gravel-capped terraces 
bordering the playa consist of a soft, fine silt, mostly red, but sometimes slightly green, 
in which are numerous thin layers of transparent crystalline gypsum. No warping 
of the silts was here observed, but the\- were seen onh- near the center of the basin. 
The Chau Bineh Basin. — At Chau Bineh, near Durukh, about 90 miles south- 
east of Birjand, thick warped clays were noted, purple, red, and green, like those 
of the Jam basin. They lie unconformably against a mass of ancient volcanic rocks 
full of serpentine and iron pyrites. The Durukh basin, on the edge of which they 
lie, is tributary- to Sistan. 
The Ouihak Basin. — This basin and the following one lie on the edge of the 
main basin of Persia, the Daslit-i-Lut, and would discharge into it if supplied with 
sufficient water. Yet each possesses its own individuality and is a separate basin 
with its own "kavir" or salt playa occupying the lowest portion. The basin of 
Chahak lies two days' journey, 40 or 50 miles, northwest of Birjand, on the road to 
Tun. Around the playa at the bottom of the basin the waves of a fonner lake, 
have cut bluffs of considerable height. For the most part these are composed of a 
hard cla>- shale, partly green and partly red, which usually lies horizontal, although 
in some places it is much folded. Three or four miles northwest of the village of 
Chahak the bluffs, about 100 feet high, are capped with la\'a and disclose the 
following section, beginning from the top : 
Feet. 
Dark volcanic trap 20 
Green clay shale 40 
Pink shale 10 
Yellow clay shale S 
Green clay shale 20 
