214 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 1 7, 



The Island of Tenedos is still more interesting and instructive in 

 respect to the relative position of the freshwater deposits, and for 

 their greater development, as seen in fig. 2, p. 213. 



Here the freshwater deposits are found to be capped by about 

 40 feet of a white arenaceous limestone, containing marine shells of 

 the present sea, both deposits lying nearly horizontal, and apparently 

 conformable. The exact place of separation of these two groups is not 

 easy to be detected; and it was some time before I discovered positive 

 proof of the freshwater origin of the lower group of strata, c and d 

 in the section. 



Three-fourths of the island is comprised of these horizontal beds 

 of freshwater and marine tertiaries, which together are fully 100 feet 

 thick. The other fourth consists of a conical peak of trachyte 

 (Mount Elias), rising like a dome over the extreme north-east cape 

 of the island, and throwing off from its southern flanks ridges of 

 secondary limestones and shales, somewhat frizzled by the contact ; 

 these are succeeded or overlaid by horizontal strata of the Tertiary 

 series, as shown in fig. 2. 



The fossils which I procured from the bed d are a small Paludina, 

 Planorbis, Neritina, Cyrena (?), Melanopsis, and a ribbed bivalve 

 (Cardium) similar to the one found in the Dardanelles deposits near 

 Meitos and over Nagara Point. 



The deposit a contains shells similar to those of the present sea ; 

 and, although they are upwards of 100 feet above the sea-level, they 

 are apparently of a late Tertiary age (older or newer Pliocene), like 

 the marine deposits which repose against the freshwater beds at the 

 south-east extremity of the island of Cos. 



To the north of Cape Baba, near the River Touzla, there are some 

 coast-cliffs of this late marine tertiary, from 30 to 40 feet high, in 

 which the beds seem to repose on the adjacent igneous rocks. The 

 latter extend northward to the mountains at the back of Alexandria- 

 Troas, where a granitic trap predominates, and from whence columns, 

 in early days, and stone-shot for the guns of the Dardanelles, in 

 later times, have been quarried. These quarries occur near the 

 village of Chimali. 



More to the northward, the blue semi- crystalline limestone and 

 shales of the secondary group of rocks replace the volcanic rocks ; 

 and then succeed extensive districts of horizontal strata of the fresh- 

 water and marine tertiary deposits, as far as the Dardanelles, Sea of 

 Marmora, and Constantinople, with an occasional protrusion of the 

 trap here and here in the northern part of the Troad. 



Connected with these jets of trap, between the Gulf of Smyrna and 

 the Troad, outlying from the great centres of eruption, is an in- 

 teresting point which I observed many years ago when examining and 

 surveying the topography of the plain of Troy, to illustrate the 

 Homeric history, and when I was accompanied by my learned friend 

 Dr. Forchhammer of Kiel, who wrote an account of our trip for the 

 ' Geological Journal.' Several masses of basaltic rocks peep through 

 the tertiary strata forming the hills surrounding the plain of Troy ; 



