V 
VIII CONTENTS. 
Page. 
The Tertiary history of the basin of Eastern Persia 242 
Persia as a typical example of an arid country 246 
The cycle of erosion and deposition in Persia 246 
Youth 246 
Maturity 247 
Old age 251 
Persia as an example of the influence of changes of climate 253 
]/ Theories of terrace formation 254 
Examples of terraces 254 
The northern slope of Kopet Dagh 254 
The Murg-ab River 257 
The Heri Rud 258 
Tlie lake of Kogneh Nemeksar 260 
The Salt lake of Pul-i-Khatun 263 
Nemeksar, or the playa of Khaf 264 
Kulbcrcnj 265 
Terraces among the mountains from Meshed to Birjand 266 
The terraces on the borders of the Dasht-i-I,iit 267 
Terraces in Turkey 271 
Terraces in North America 272 
The nature and the method "f action of the Quaternary climatic changes of Eastern Persia. 273 
Sistan 276 
The Helmund River 276 
Description of Sistan 277 
The delta of the Helmund 281 
The Shila and the Ciod-i-Zirrah 283 
The Quaternary era in Sistan 285 
The deposits of the lake of Sistan 285 
Lake deposits versus playa deposits 286 
The cause of the alternations of the Sistan strata 288 
Outlet theory 288 
Diversion theory 288 
Rhythmic warping theory 289 
Fluvial or lacustral theory 290 
The gravels of Sistan 291 
The terraces of Sistan 293 
Northwest side of the lake 293 
Southeast side of the lake 295 
Modern shorelines 295 
Younger abandoned shorelines 295 
Older abandoned shorelines 299 
Climate and history 302 
■^ The ancient climate of Iran 302 
Alexander's march 303 
The desiccation of ancient ruins 30S 
Neh 306 
The Merv oasis 307 
Bal Kuwi and Anau 307 
The northern border of the Dasht-i-Lut 308 
The cause of the depopulation of Iran 308 
The legendary history of Sistan 312 
Agreement of legend, history, and physiography 313 
Bibliography 316 
