1857.] SPRATT DOBRUTCHA. 211 



cliffs, as I have shown previously. Chalky downs are always highly 

 favourable to the prolific development of land-shells, as is well known 

 to all naturalists. And I digress for a moment to suggest that, in this 

 view, we have an explanation also of the origin of the white marly 

 character and great thickness of the Baljik freshwater deposits, as 

 having been derived from the denudation of these great chalky ridges 

 by the torrents of every season's rain. Here also the land-shells 

 (Helix) are as abundant in the upper series of the deposits as the 

 bivalves and other freshwater shells that lived in the lake. 



Referring to the section, I have to add that the fossiliferous 

 bands of the lower freshwater series thin out sometimes to a thick- 

 ness of a few inches at distances of a few hundred yards on either 

 side : such is the case towards Kustenjeh, where, being less indurated, 

 they have been superficially denuded, as shown in fig. 5, a. 



At the locality where the last-described section was taken, how- 

 ever, the greenish marls present a flat surface, upon which imme- 

 diately succeed the reddish marls of the upper series, which I have 

 before described as being stratified in thick beds of dark-brown, grey, 

 or reddish marls ; they are nearly 100 feet thick in some parts. The 

 upper marls are lighter and somewhat porous *. 



In closing my remarks, I shall merely state that I have no doubt 

 but that the continuity of the Kustenjeh freshwater deposits will 

 be traced hereafter up to the elevated deposits of Baljik, as a con- 

 tinuation of the bottom of the same lake. And I venture to suggest 

 that thev are also identical with those of Odessa and Kertch, neither 

 of which, however, I have had an opportunity of examining. Their 

 connexion is to ray mind also certain with those of the shores of the 

 Sea of Marmora, by the valley of Brujuk Tchekmijeh, where I some 

 time since found freshwater fossils in its deposits, together with a 

 band of lignite. Also the lignite and gravel-beds examined by Mr. 

 H. Poole f on the south side of the Sea of Marmora, near Brusa and 

 Ismid, I believe to be of freshwater origin ; and I connect them as 

 indications of one great eastern freshwater lake that existed perhaps 

 from the Miocene to a late Tertiary period. The actual limits of 

 this lake westward as well as eastward have yet to be defined by 



* The specimens from the " Upper series of the Steppe deposits," sent to the 

 Society, comprise — 1. red marl; 2. soft, yellow, laminated, argillaceous sand- 

 stone; 3. brownish, sandy, micaceous marl; 4. a brownish marl, like No. 3, but 

 altered by atmospheric agency, perforated with minute irregular tubules (as is 

 also No. 3), and containing small, soft, calcareous concretions ; 5. like No. 4, but 

 less calcareous, and redder ; also buff- and salmon-coloured calcareous concre- 

 tions, and soft white marl. 



The specimens of the "Freshwater series" comprise — 1. shelly, cream-coloured, 

 compact limestone, full of casts of Helices and a Bulimus ; 2. hard, grey, shelly 

 limestone (weathered), concretionary or oolitic, and crystalline, full of casts of 

 bivalves (Cyrena ?), and containing a few casts of small univalves ; 3. marly lime- 

 stone, full of casts of Cyrena ?, passing into a hard, grey crystalline limestone, 

 with similar casts, and resembling No. 2 ; 4. greyish limestone, full of casts of 

 Cyrena ?, interior of the casts sometimes oolitic ; 5. grey limestone, full of hollow 

 black moulds of a small Paludina ; 6. green clay, with a portion of an elephant's 

 tusk. — Edit. 



f Quart. Journ. Geol. Soc. vol. xii. p. 1, &c. 



