On the Geology of the Princes Islands, in the Sea of Marmora, Turkey

Abstract

1. Introduction .—It was during a visit to Prinkipo, the largest of the Princes Islands, in the summer of 1864, that I first had an opportunity of studying the geological features of that island; and the discoveries I then made were of so interesting a character as to induce me to continue the examination of the remaining eight islands. Before going into a detailed account of each island, I will here relate some of the chief points of interest met with, namely:— (1.) The existence of a considerable tract of Devonian strata, partly fossiliferous, in several of these islands, of an age different from that of the beds of the Bosphorus, which latter I have already shown, in a former paper to the Geological Society†, to belong to the lowest of the Devonian series of the Rhine. Also the existence of the remains of “fish” in the above strata, and an ancient “coral reef.” (2.) That the rocks which form the remaining portions of these islands are trachytic, and of younger age than the Devonian strata. (3.) That the trap rocks of these islands are of younger age than the trachytic. (4.) That the quartz rocks, of which some of the islands are largely, and some entirely composed, are altered sandstones of Devonian age, which clearly explains the occurrence of similar quartz rocks on the Bosphorus, which are seen in the mountains of Bulgurlou and Tchemlidja, behind Scutari, and referred to by Mr. Hamilton in his “Observations on the