t360 ME. E. T. GtTNTHEE OK THE 



Islands. — In the southern half of the lake is a small group of 

 rocky islands whicli from a distance present a rounded appearance, 

 like the knolls on our chalk downs, but from a nearer point of 

 view their precipitous cliifs and rugged hill-sides testify to the 

 erosive powers of the heavy salt waves in stormy weather. Their 

 geological structure has been investigated by Abich, who pro- 

 nounced them to be built of Miocene chalk resting upon Palaeo- 

 zoic calcareous strata which are to be seen near the north end of 

 Koyun Daghi. The Miocene chalk is divisible into three main 

 divisions. The uppermost is porous and contains Ostrea Virleti, 

 Deshayes ; the middle division is of a more compact nature and is 

 rich in corals. In the lower deposit bivalve and coral fragments 

 are found, together with Turritella ArcTiimedis, Brongniart, 

 T. turris, d'Orb., and T. gradata, Menke. 



On many of the islands are beaches of shells, coral fragments, 

 and echinoderms, organisms which could have lived only in 

 a sea of marine salinity and in connection with the ocean. 

 These marine reliquiae, now for a second time rolled by salt waves, 

 tell the tale of a Miocene sea of normal salinity which has been 

 supposed by Pohlig to have been a northerly continuation 

 of the Persian Grulf from the Indian Ocean, but which, as 

 already stated, was more probably an extension of the Mediter- 

 ranean. This Miocene sea, like the Red Sea of to-day, was a 

 coral sea. Upon its floor were laid down the chalk and lime- 

 stone formations of the TJrmi Archipelago, as well as those of 

 the calcareous mountains to the south of the lake. 



The largest of the islands are Koyun and Arzu, of which the 

 former measures between 3 and 4 miles in length and rises to a 

 height of about 1000 feet above the level of the lake. 



The islands appear to have been formerly inhabited, and there 

 may still be seen foundations of houses near a spring at the 

 south-eastern end of Koyun Daghi. At the present time 

 they are uninhabited, but are often visited by sailors, who 

 turn out goats and sheep to pasture on them during certain 

 months in the year, and who not only cut down the trees, but even 

 dig up for fuel the roots of trees felled by their predecessors. 

 There is a tradition that some eighty years ago the islands were 

 connected with the mainland by a causeway which can, it is said, 

 still be detected by sounding. This tradition is certainly con- 

 firmed by the zoology of the islands. There are at least five species 



