494 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 11, 



aridity, small rainfall, absence or scarcity of rivers, and paucity of 

 cultivated land, combined with the same recurrence of broad desert 

 plains surrounded by barren mountains. 



Physical Geography and Rainfall of Persia. — But an imperfect idea 

 of tbe physical geography of Persia can be obtained from maps. The 

 country consists of a great plateau from 1200 to 3000 feet above the 

 sea, or rather of a series of plains of that height, separated by smaller 

 ranges from each other, and divided from the lowlands of Turkestan 

 and the Caspian provinces to the north, the Tigris and Euphrates 

 valleys to the west, Laristan and Baluchistan to the south, and India 

 to the east, by a broad belt of mountainous country, containing 

 within itself wide valleys from 5000 to 8000 feet above the sea. Thus 

 the central plateau consists of a number of basins without any out- 

 lets* ; and the few streams which run into these lose themselves 

 in salt marshes and sandy plains. From the conformation of the 

 ground, it is evident that the rainfall in the central region must be 

 small, since all damp winds, in converging towards it, are driven up 

 to greater altitudes and compelled to surrender a large portion of 

 their moisture on the outer slopes of the surrounding ranges. Thus 

 it is that the south-western slopes of the hills extending from the 

 neighbourhood of Shiraz along the north-east side of Mesopotamia, 

 and the northern watershed of the Elburz mountains facing the 

 Caspian Sea, are clothed with forest, whilst the inner slopes of the 

 same ranges towards the central plateau are barren. Yet rain and 

 snow, frequently in heavy falls, are by no means unknown in winter 

 in Central Persia ; thus in 1871-72 the famine at Tehran, Isfahan, 

 Kashan, and other towns was greatly aggravated, if not to a con- 

 siderable extent caused, by all communications with the surrounding 

 country being cut off by heavy snow-drifts. Kashan is but 3000 feet 

 above the sea, and it is on the edge of the great desert of North- 

 western Persia ; yet the quantity of snow was sufficient for people 

 to be lost in it. The rainfall, however, is, as a rule, confined to the 

 winter months. There is thus in Persia one element of rapid and 

 effective denudation present, viz. the concentration of the rainfall. 

 Another important aid in the work is the occurrence of severe frosts, 

 the winter being excessively cold, even as far south as 30° IS", lat. 



The paucity of rivers in Persia has been noticed by many tra- 

 vellers in the country ; and I can only add, as my own experience, 

 that in a journey from the Indian Ocean at Gwadar, within 200 

 miles of the Indian frontier, to Besht near the Caspian, via Jalk, 

 Bampur, Karman, Shiraz, Isfahan, and Tehran, I crossed but two 

 streams (that commonly known as the Bandamir, near Persepolis, 

 and the Safed Bud, which runs into the Caspian near Besht) 

 which are not easily fordable, as a rule, at all seasons ; and I do 

 not think that, in the whole journey of upwards of 1500 miles 

 I crossed a dozen streams more than 6 inches in depth. Of course, 



* Kecent researches render it probable that these plains are by no means so 

 extensive as they are represented on the maps, but that they are much broken 

 up by low ranges of hills. The general surface may be considered a series of 

 very broad valleys, without rivers and without outlets. 



