the Western Part of Asia Minor. 15 



§ 4. Tertiary Lacustrine Deposits. (PI. III., Sec. 1, 3 to 6, and 9.) 



These deposits occupy a large portion of the surface of Asia Minor. We have 

 already stated our beUef (p. 13) that the schistose and cretaceous rocks, towards 

 the close of the secondary period, were raised above the surface of the ocean, 

 and formed that tumultuous mass of mountains which still intersects the country. 

 It would seem, that the inequalities of surface thus produced, gave rise to numerous 

 inland lakes, whose vast calcareous deposits denote a long period of comparative 

 tranquilUty. At length, by the slow denudation of their rocky barriers, aided 

 probably by the convulsions incident to a volcanic country, these lakes were 

 drained, and the rivers assumed the geographical positions which they still oc- 

 cupy. In the parts of Asia Minor which we visited, nearly every large valley was 

 found to contain these lacustrine deposits ; but in the more narrow ravines of the 

 mountain-chains, nothing of the kind was noticed. This fact may enable us to 

 distinguish the modern valleys of denudation from those older depressions, which 



were caused by the original elevation of the mountains. 



v^ 



The lacustrine formations of Asia Minor consist, in general, of calcareous marl and white limestone. 

 The latter is often identical in composition with the chalk of England, and the resemblance is further in- 

 creased by the presence of beds and nodules of black flint. Sometimes the limestones are more compact, 

 and approach in character the Italian scaglia or the Bavarian lithographic stone. Towards the margins 

 of the lacustrine basins, the marls and limestones gradually become sandy and then gravelly, and not un- 

 frequently traces may be found of a regular shingle beach*. (PI. III. Section 5.) 



The lacustrine strata are, with few exceptions, nearly horizontal, and seem in general to have remained 

 undisturbed since the period of their deposition. The lapse of time however has subjected these deposits 

 to extensive denudation, and sometimes nothing remains of them, but a few detached platforms, which skirt 

 the sides of the valleys at the same level, and show the precise form and extent of these ancient lakes. 



The organic remains which occur in these deposits, consist of lacustrine shells and portions of vege- 

 tables. They approach very closely to existing forms, though we do not venture to assert a completely 

 specific identity in any of them with the present Fauna or Flora of Asia Minor. No remains of 

 Mammalia or other Vertebrata were noticed during our rapid survey of these deposits ; and we wish to 

 call the attention of future travellers to this desideratum in the geology of Asia Minor. 



We now proceed to enumerate the localities at which we met with deposits of 

 this class, though we do not pretend to assert the absolute contemporaneity of all 

 these detached lacustrine basins. 



(a.) The basin of Moudania (lat. 40° 23', PI. I.). — The country between Mount 

 Olympus and the sea of Marmora is occupied by a tertiary formation, but no fossils 

 occurred to us in it. Near Moudania it forms hills overlooking the sea, and 

 several hundred feet in height. The similarity of the white limestone of the 



* To the eastward of that part of the country, now more immediately under consideration, beds of 

 selenite and gypsum occur in some of the upper portions of the formation, as between Sevrihissar and 

 Afiom Karahissar. 



