SPRATT — BULGARIA. 11 



must have been also covered subsequently by the group of red marls, 

 &c., and entirely denuded again), we have the fact or idea of the 

 Devno Valley and Varna Bay having been formed by a depression of 

 comparatively recent date. 



North of Varna. — I shall now make a few remarks upon the de- 

 posits lying north of Varna, towards the Danube and the Dobrudcha. 

 A line of steep banks or cliffs extends from Varna to Cape Kaliakra, 

 which are everywhere formed of the yellowish limestone and sandy 

 marls, with a thickness of from 400 to 500 feet ; and this group 

 extends to near Mangalia, where the overlying reddish sands and 

 marls take their place, and form generally the Steppe-country of the 

 Dobrudcha. The ridges or plateaux of the latter district attain 

 generally an elevation of between 200 and 300 feet, as in the direct 

 line across from Kustenjeh to the Danube. On this line, rocks of 

 the older Tertiary period are exposed at the base of the reddish marls 

 and sands, on the edge of the lower Korason Lake, but are not seen 

 on the Black Sea shore of the Dobrudcha. At Baljik the edge of the 

 steppe is nearly 600 feet above the sea. 



These deposits are generally less indurated than at Varna, and are, 

 for the most part, more marly, passing, in some strata, into an indu- 

 rated calcareous marl. The upper portion, for nearly 100 feet, is a 

 white and grey marl, of fresh-water origin, and apparently conform- 

 able with, or passing gradually into, the marine deposits below ; both 

 being nearly horizontal. The freshwater deposits appear to have 

 resulted from the waste of some of the former, although somewhat 

 more sandy. Land-shells are also found in some of the overlying 

 beds of white arenaceous marls above the purely freshwater deposits. 

 The whole are here capped by a few feet of a red earthy marl, that 

 seems to belong to the second group of deposits, usually red or brown; 

 and to connect those below, of freshwater origin, with them also. 



[In a letter* received since this paper was read, Capt. Spratt says — 



Having touched at Baljik for two or three hours in August last, 

 I had an opportunity of making additions to my former account of 

 its formations. I found the general distribution of the strata to be 

 as follows : — 



At the base are 1.50 or 180 feet of dark-grey and brownish marls, 

 thinly laminated, and containing numerous marine fossils, generally 

 very minutef . These marls form apparently an upper member of 

 the Varna series. They lie nearly horizontal, and are overlaid by 

 about 200 feet of a white thick-bedded marl, containing only casts of 

 a small striated bivalve, like a Cardiwn^ especially like the one in 

 the freshwater deposits of the Dardanelles. 



This mass of white chalky-looking marl seems to be unconform- 

 able to the lower marine bed, although nearly horizontal also. I 

 think that probably it is of brackish-water origin : it passes upwards 

 into a series of white and greyish marls, indurated occasionally in 



* Read at the Evening Meeting, December 3, 1856. 



t A small packet of this shelly deposit has been brought to England by a friend 

 of Capt. Spratt. The shells are small, and prove to be Trochus, Buccinum, Bulla, 



