180 Dr Boue's Gcograpldcal and Geological 



Immediately above these older rocks of the Balkan we find 

 a \\\\c^ formation of green sand, composed of marly greyish 

 sandstones, quartzose and greenish-coloured sandstones, and 

 beds of marly clay and whitish, greyish, or black compact lime- 

 stone. The latter rock is often conchiferous as at \Vikrar, where 

 some of the beds contain oysters, pectens, naticas, turbinated 

 shells, cariophyllea?, and other coralline bodies. In some cases 

 orbitolites occur in great numbers, as near Loftdscha. The 

 limestone forms thick beds, and occasionally craggy precipices ; 

 but the other rocks, with the exception of some of the green 

 sandstones, only form hills, which are generally either covered 

 with oaks and elms, or, being destitute of trees, are used as 

 pasture grounds. The beds of the lowest cretaceous formation 

 are not exactly parallel to the general direction of the Balkan, 

 but appear to intersect it at a very acute angle, deviating a 

 little to the south. The general dip is nearly N.NE. ; but the 

 undulations of certain masses often causes the dip to change to 

 the S.W., N.W., &c. 



At the eastern extremity of the Balkan, the green-sand is 

 covered by extensive plateaux of chalk, with flints and belem- 

 nites. Chalk appears on all sides when it is not covered by the 

 vegetation. Schumla is a good place for seeing the transition 

 from the uppermost green-sand to the chloritic chalk with its 

 fossils, the Grypheae (G. auricularis, G. vesiculosa), Inocera- 

 mu3 (/. sulcatus), Pecten, Lima, Terebratula, Cucullea, Nerina, 

 Natica, Cellepora, Flustra, Galerites, &c. ; and also the transi- 

 tion from this last to the chalk with its characteristic fos- 

 sils, the striated terebratulae, shark's teeth, &c. The beds 

 around Schumla are in an anticlinal position, and the town oc- 

 . cupies the centre of the convexity or rent. By the aid of a little 

 imagination it might be regarded as a crater of elevation, in 

 which are deposits of tertiary clay, forming towards the east 

 the natural double ramparts in the semicircular form of the 

 town. On the other side it is inclosed by chalk hills, upon 

 which a citadel and redoubts have been erected, in order to pre- 

 vent the approach of enemies from the plateau. These chalk 

 hills have been delineated by geographers as advanced portions 

 of the Balkans ; but certainly they ought not to convert mere 

 small hills into chains of mountains. 



