. The Quarterly journal of the Geological Society of London. o leave one or more lakes draining north-eastwardthrough the Bosphorus river, and the water in these would befreshened and lowered as the Bosphorus valley gradually attainedits present general profile at some time during the Pliocene Period. Then the level of the Ponto-Caspian lake commenced again torise, so that, in correspondence with this, the Sea of Marmoragradually extended its limits westward to Gallipoli, and thebrackish-water bed of Caspian shells, that now forms the con-glomerate upon which the town is built, was deposited.
. The Quarterly journal of the Geological Society of London. o leave one or more lakes draining north-eastwardthrough the Bosphorus river, and the water in these would befreshened and lowered as the Bosphorus valley gradually attainedits present general profile at some time during the Pliocene Period. Then the level of the Ponto-Caspian lake commenced again torise, so that, in correspondence with this, the Sea of Marmoragradually extended its limits westward to Gallipoli, and thebrackish-water bed of Caspian shells, that now forms the con-glomerate upon which the town is built, was deposited. The rise ofwater gradually reached the height indicated by the beach at Hora, Fig. 6.—Raised beach, 130 feet above sea-level, at Hora lighthouse,north-western coast of the Sea of Marmora. (See pp. 263, 265.) 1 1 -*-- jA-; ... Wtt^AJPMJM^^- *£*fe^SiL ?^ -w tip^jx •--^ LL J ^^ Hv abk,^. t PJP^^PT; W/ •SB *• r ? • - *!£*- ^^B^fe HEBBteai^j % ? ???-. ^1 ^9 **%• Fig. 7.—Ancient river-channel at Maitos, Dardanelles. (See p. 265.). Vol. 60.] EOCENE, ETC. SURROUNDING THE DARDANELLES. 265 130 feet above sea-level, containing Neritina fluviatilis ( = danu-bialis), Didacna crassa, Dreissensia polymorpha, and Mytilus beach commemorates the last high-water mark of the Ponto-Caspian closed basin, and probably followed a portion of the contourof the Marmora lake at the time when the Gallipoli shell-bankaccumulated (fig. 6, p. 2(34). The conglomerate-rock, upon which Gallipoli is built, consists ingreat part of shells of Didacna crassa, Dreissensia Tschaudce, andDr. polymorpha. The deposit is not, in nry opinion, a raised beach,and it is about double the height generally stated. It is spreadout over at least 2 square miles, with a fairly-uniform surfaceabout 80 feet above the water. At Bas-Chesme Bay (Gallipoli), theconglomerate is partly replaced by a local bed of sandy loam, inwhich is a seam, about a foot thick, of the same Caspian shells{Didacna crassa and D
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
