Geological Society. 515 



scattered, not collected in great mountain masses. The Katake- 

 kaumene.in Mr. Hamilton's opinion, exhibits also additional evidence, 

 that the disposition of comparatively recent volcanos is coincident 

 with the strike of the granitic axis, from the interior of which the 

 volcanos have burst forth. The author also alluded to other com- 

 parative phenomena noticed in Mr. Strickland's paper. Lastly, he 

 pointed out two distinctions : — in Central France streams of igneous 

 products may be traced from the most ancient volcanic masses 

 of Mont Dore, but in Asia Minor none have been detected which 

 could have flowed from Ak Dagh, or Morad Dagh. In France, 

 also, trachytic eruptions occurred during the deposition of the lacus- 

 trine limestone ; but in the Katakekaumene, they appear to have 

 preceded that of the white limestone, or are associated with only its 

 lowest beds. 



In conclusion, the paper gives a general summary of the geological 

 phenomena of the country south of the Demirji range. 



The relative antiquity of the vast lake or sea in which the strata 

 were deposited, cannot be determined, as the micaceous sandstone 

 forming the lowest series of beds is apparently destitute of organic 

 remains, and Mr. Hamilton, therefore, does not attempt to compare 

 that deposit with any European formation. The sandstone, he con- 

 ceives, was accumulated upon an irregular surface of schistose 

 rocks and crystalline limestone, and before the elevation of the 

 Demirji chain. Upon the sandstone were deposited in the north of 

 the district the beds of peperite, derived probably from subaqueous 

 volcanos ; and upon the peperite and the micaceous sandstone, the 

 white limestone, which is the highest sedimentary rock. The drain- 

 age of the lake, he is of opinion, took place during the earliest 

 volcanic eruptions of the Katakekaumene. 



Three well-defined periods of igneous operations may be traced. 

 The first is marked by the masses of basalt which cap some of the 

 plateaux of white limestone, and were ejected previously to the 

 country assuming its present configuration, and to the formation of the 

 valleys. Mr. Hamilton considers that the basalt flowed under water, 

 and probably but a short time before the drainage of the lake. 



The second period is characterized by the currents of basalt and 

 lava from the ancient system of volcanos in the Katakekaumene, 

 and was subsequent to the formation of the present valleys, as 

 many of the lava streams may be traced into them. The couldes 

 which flowed towards the Hcrmus from the crater or Karadevit near 

 Koola, present an inclined plane, the surface of which is not more 

 than 150 or 200 feet above the present bed of the river ; but they 

 must, at one period, have been under water, as the lava is covered 

 with a sediment which fills its crevices and smooths its asperities. 



The third jieriod belongs to the more modern system of cones, 

 the lava of which is as rugged and barren as the recent coulees of 

 Etna and Vesuvius. Of the date of these erujjtions, Mr. Hamilton 

 offers no ojiinion, merely remarking that the craters are mentioned 

 by Htrabo, and that there is no tradition of their activity. 



March '27. — A paper was read l)y Prof. Owen, F.Ct.S., entitled a 

 •JL2 



