Gli Geological Society. 



8 01- 10 feet tliick, occur around the mouths of the springs ; and a 

 strong sulphureous smell accompanies the emission of the M'ater ; but 

 where the temperature had become sufficiently low to permit the 

 water to be tasted, no peculiar flavour was perceived. After flowing a 

 mile and a half and turning several mills, the water is used for a 

 warm bath. The rock from which the springs rise, is a greenish 

 brown porphyritic trap. Some copious hot springs issue near the 

 lower beds of the tertiary white limestone, a little north of Koola, 

 the temperature A'arying from 123° to 1 37° Fahr. Two of them are 

 situated in the centre of the ruins of an unknown ancient city. Mr. 

 Hamilton perceived a slight development of sulphuretted hydrogen 

 gas. 



The Katakekaumene. — The extent of this interesting tract is much 

 less than is assigned to it in published maps, being not more than 7 

 miles from north to south, and 18 or 19 from east to west. After 

 alluding to his first visit to it in company with Mr. H. E. Strickland, 

 and referring to that gentleman's account of a portion of the district*, 

 Mr. Hamilton describes minutely the two systems of volcanos, di- 

 stinguished by the state of preservation of the craters and of the 

 coulees : he defines also the course of each lava-current, and points 

 out its attendant phenomena — but these details admit of only partial 

 abridgement. 



The volcanic products are basalt, lava, and ashes, the first being 

 confined to the more ancient craters, and the last to the more modern. 

 The numerous older cones are further distinguished by being situated 

 on parallel ridges of gneiss and mica slate, and the newer, only three 

 in number, by being confined to the inter^'ening alluvial valleys. 

 This important distinction Mr. Hamilton explains on the supposition, 

 that the elevation of the schistose ridges produced cracks, through 

 which, as points of least resistance, the first eruptions of lava found 

 vent ; and that these openings becoming subsequently plugged up, 

 by the cooling of injected molten matter, the schists were rendered 

 so solid, that when the volcanic forces again became active, the lines 

 of least resistance were transferred to the valleys. 



The coulees from the ancient craters appear to have been partly 

 under water, as their surface is, in some places, covered with sedi- 

 ment and turf; but the lava streams from the modern are bare, rugged, 

 and barren, and the craters are surrounded by mounds of loose 

 scorise and ashes. In addition to the comparative view given by 

 Mr. Strickland of the phenomena of the Katakekaumene and Central 

 France, Mr. Hamilton enters into a more extended investigation of 

 points of resemblance, including other portions of Asia Minor. The 

 great volcanic groups of Mont Dore, the Cantal, and Mont Mezen, 

 Mr. Hamilton conceives are represented by Ak Dagh, Morad Dagh, 

 the trachytic hills east of Takmak, Hassan Dagh, and Mount 

 Argseus. The modern volcanic period of Central France he com- 

 pares with the Katakekaumene, as respects the composition of the 

 lavas, their arrangement at difi'erent levels, and the cones being 



» See L. & E. Phil. Mag. vol. x., p. 70. 



