352 ME. E. T. G0NTHEE ON THE 



into three well-characterized equivalent zones, which hare been 

 defined by Pohlig as : — 



Zone 1. The marginal zone of sandstones, conglomerates, and 

 gravels, often containing organic remains from earlier 

 strata. The Seir hill probably belongs to this zone. 

 Zone 2. Light-coloured marls, generally bright red, with beds 

 of rock-salt and gypsum. Both zones 1 and 2 take a large 

 part in the formation of the hills of the Persian plateau. 

 Zone 3. Limestones and calcareous marls ; best seen in the 

 islands in the Lake of Urmi, but also in the mountains to 

 the south-west, and which are very rich in molluscs, reef- 

 building corals, and silicious sponges. 

 At Guverchin Kala, near the northern end of the lake, the 

 entire series of Miocene strata rest almost horizontally and 

 directly on red granites traversed by felspar-dykes, which are a 

 very conspicuous feature in the landscape. 



Urmi must therefore have been covered by a sea of normal 

 salinity in Miocene times, which was apparently an extension of 

 the Miocene Mediterranean Sea. Then commenced those vast 

 changes of level which resulted in the upheaval of a Miocene 

 sea-bottom some 5000 feet to its present position as part of the 

 Persian plateau ; this vast earth-movement is still clearly recorded 

 by the numerous volcanoes and outbursts of volcanic rock which, 

 monument-like, mark the spots where the earth-crust gave way 

 before overwhelming strains and irresistible pressures. The 

 next chapter in the story of Urmi tells iis how at a later date the 

 dry land about Maragha supported a mammalian fauna, which 

 must have been very similar to the almost contemporaneous fauna 

 of Samos and of Pikermi in Greece. The bones of herds of 

 elephants, antelopes, and horses, as well as those of many other 

 mammals, are to be found preserved in the pumiceous tufa- 

 deposits of Kirjawa near Maragha (p. 376) ; it is still uncertain 

 whether or not the animals perished in consequence of a volcanic 

 eruption or from some other cause. 



During Pliocene and post-Pliocene times the land undoubtedly 

 underwent considerable changes both of level and of contour. 

 There is no evidence that the present lake is the remains of a 

 Miocene sea, and therefore it is not to be regarded as a " Eelikten- 

 See," a view which is also shared by Eodler. The excellent Ameri- 

 can monograph on Lakes Bonneville and Lahontan is an example 

 of how the physical geographer has been able to reconstruct 



