The tableland of the interior, thus walled in by mountains, is itself intersected by numerous ranges and detached masses of mountains, ex cepting in Eastern Persia, where great plains and deserts are the main topographic feature. Between these ranges, also extending northwest and southeast, are wide plains and narrow valleys. These plains and valleys would be ut terly sterile were it not for the mountains near them, which collect rain and snow. The valleys are more easily irrigated ,and are thus more fertile than the plains, which are here and there brightened by a patch of green oasis, but for the most part are sandy and barren. The general aspect of the plateau is that of a cheerless and monotonous waste stretching to the base of moun tains that are equally bleak and uninviting, and reaching the acme of frightful desolation in the two deserts of the east, the Dasht-i-Kavir or Great Salt Desert, extending between latitudes 33° and 36° N., and from longitude 52° to 57° E., and the more southerly Dasht-i-Lut or Great Sand Desert, extending between latitudes 29° and 32° N., and between longitudes 57° and 60' E. Their combined length is over 500 miles from northwest to southeast, but they are separated between the thirty-second and thirty-fourth parallels by a hilly region through which passes one of the main caravan routes between Central Persia, and Meshhed. The origin of the Great Salt Desert is not yet clearly determined. One theory is that it is due to the drainage of saline streams from the surrounding higher lands and the consequent deposition of a white crust or efflorescence; the other theory is that it is the bed of an ancient salt lake. Geologists now in cline to the latter explanation. In 1891 a solid bed of rock salt estimated at over 600 square miles in area and several feet in thickness was discovered in this remarkable region. Lieuten ant Vaughn and Mr. C. E. Biddulph, who brought to light this sea of solid rock salt, which is probably unrivaled in the world, found it so hard that with iron tent pegs they were able to detach only a few chips.
The Dasht-i-Lut or Great Sand Desert, which separates the Province of Khorasan from that of Kirmarr, has salt also as one of its chief in gredients, but it is rarely overlaid like the more northern desert with saline incrustations or briny swamps. It gives life to a few poor
shrubs, while nothing grows in the other desert. Sand is its prevailing feature. It is much lower in altitude than the Great Salt Desert, its aver age elevation being less than 2000 feet, while in places it sinks to only 500 feet above sea-level. All these topographic aspects have a marked effect upon the distribution of the population. The lines of villages and cities follow the trend of tire mountains from east to west across North Persia and from northwest to southeast across Western and Central Persia. because only in the neighborhood of the mountains can water be obtained to supply the towns and nourish the gardens and fields. Where the ranges spread far apart, and in Eastern Persia, where there are few high elevations, there is only a sprinkling of human inhabitants. Desolation reigns over vast expanses.
nxOGRAPi[Y. The waters of two-thirds of Persia do not reach the sea, but are lost in in land swamps or lakes or disappear in the sands. Few rivers are worthy of special mention. Among them is the Karim, which drains a large part of the mountainous provinces of Luristan and Khuz istan, empties into the Persian Gulf, and is nearly four feet deep throughout the year. A small steamer, subsidized by the British Government, is now making regular trips 150 miles up the river to Ahwaz, where rapids and ledges obstruct navigation. No other river is navigable. The Sefid Rud, Atrek, and Gurgan, draining the northern slopes of the Elburz, and its prolonga tions, are the only considerable streams entering the Caspian. The streams flowing to the inland basins are much inferior in volume to those emptying into the sea. Only two lakes are of importance. Lake irrumiah lies in the extreme northwest and from its surface the snowy top of Mount Ararat may be seen. It is so heavily charged with salt that swimmers cannot dive in it. Its wooded shores and islets give a pleasing impression, but 4 he average depth is only about 15 feet. and, though it covers an area of about 1000 square miles, its volume is six or seven times inferior to that of Lake Geneva in Switzer land. The great salt lake of Southern Persia is enrich smaller than Frumiali and with a. greatly indented and fantastic outline.