212 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Julie 17, 



determining the precise age of the great volcanic centres, that, from 

 Ararat to Lemnos, and Santorin to Vesuvius, have from time to time 

 uplifted or submerged parts of its expansive bed. 



In merely touching upon this view, I am induced to recall to mind 

 the other isolated fragments of freshwater deposits that occur in 

 Rhodes, Crete, Cerigo, and in the western basin of the Mediter- 

 ranean, of Provence, Lombardy, Florence, Minorca, &c, as reviving 

 an old idea of a chain of lakes having existed in the Mediterranean 

 basin during this period, or rather during a portion of it. 



In the sections here given it will be seen, that the superficial red 

 earthy marls of the Steppe-series cover rocks of all ages, and that the 

 freshwater marls, d, are often wanting. The probable explanation 

 is, if the former were deposited in freshwater also, that the old land 

 surrounding the lake became suddenly submerged at the commence- 

 ment of this red marl series, — or that the level of the lake became 

 suddenly raised by the escape of water from some more extensive and 

 more elevated basin, — or that the waters were suddenly raised, having 

 been pent up within more limited bounds, on account of the rising 

 of some great mass of continent, such as a large part of Asia Minor, 

 from out of the great eastern freshwater basin which I suppose to 

 have existed. 



12. On the Freshwater Deposits of the Levant. 

 By T. Spratt, Captain R.N., F.R.S., F.G.S. 



The brief account recently published* of the extensive freshwater 

 deposits which exist on the western shores of the Grecian Archi- 

 pelago calls for a notice of those within my knowledge on the eastern 

 shores. 



The freshwater tertiaries of Smyrna and Sciof have been traced 

 by me as fragments along the eastern and southern coasts of Mity- 

 lene, as well as on the coasts opposite, — the detached and disturbed 

 condition of these deposits being due to extensive outbursts of igneous 

 rocks that form large districts within this island and on the main 

 land opposite to it. For instance, the Moskonisi and Aivali districts, 

 the Assos Range to Cape Baba, Touzla, and Alexandria-Troas, and, 

 in Mitylene, the north-eastern part of the island, including Mount 

 Lepethimus, as well as the entire peninsula west of Port Kelloni, are 

 composed of volcanic rocks. Besides these there are several lesser 

 protrusions of trap in numerous parts of the intermediate districts. 



The vicinity of Mitylene presents an interesting association of the 

 trap and the freshwater deposits, particularly to the south, as shown 

 in the following section, fig. 1. 



At Cape Vourkas we meet with the trap and tertiary strata in 

 proximity, particularly on the east short of Port Kelloni, while the 

 white freshwater marls are nearly vertical, and contain several speci- 

 mens of a small Helix. 



* Quart. Journ. Geol. Soc. vol. xiii. p. 177. 



f Described in the Society's Quarterly Journal, vol. i. p. 156. 



