392 D. A. Wray— 



we cannot be certain that it did not grow in association with the 

 Tanga plants, its absence may well be significant. It must be 

 admitted that some of the coniferous shoots from Tanga bear a 

 close resemblance to fossUs from Jurassic rocks, but the scales which 

 T have referred to Voltzia appear to be nearly allied to Lower Triassic 

 forms. Moreover, the specimens with the longer type of leaf 

 inclnded in Ullmminia agree most closely with Upper Permian and 

 Triassic species. 



A few imperfectly preserved plant fragments are recorded by 

 Mercenier ^ from localities in the Belgian Congo, a few miles ^^est 

 of Lake Tanganyika. So far as it is possible to base an opinion on 

 the sketchy published draAvings. the fossils would seem to support 

 Mercenier's view that the rocks mav correspond in age to the Ecca 

 series of South Africa. iSTo examples of Glossopteris are mentioned ; 

 a piece of a Noeggerccthiopsis-like leaf is figured and portions of some 

 Lepidodendroid stems. The specimen referred by Mercenier to 

 Stenopteris elongata Carr, is not determinable. 



EXPLANATION OF PLATE XVII. 



FIG. 



1. — ? EretmopJiyllum sp. Nat. size. 



2. — UUmannia sp. Nat. size. 



3. — UUmannia sp. IJ nat. size. 

 4, 5. — Detached leaves of UUmannia. 2| nat. size. 



6. — UUmannia sp. If nat. size. 



7. — ? UUmannia sp. Nat. size. 

 8, 9. — VoUzia sp. Twice nat. size. 



The Karstlands of Western Yugoslavia. 



By D. A. Wray, M.Sc, F.G.S. 



IXTRODUCTORY. 



WESTEEN YUGOSLAVIA, which broadly corresponds to the 

 ' ' ancient Roman province of lUyricum, includes Dalmatia, 

 Herzegovina, and Montenegro, together with the western portions 

 of Slovenia, Croatia, and Bosnia. It is a region of high geological 

 interest, for within it and the adjoining portions of Italy the " Carso " 

 or " Karst " lands are developed on a scale perhaps unequalled 

 elsewhere. Considerable attention has been devoted from time to 

 time to their leading features by Austrian, Italian, and Serbian 

 geologists, though the study of these land forms has hitherto received 

 but little attention in England. Xo excuse therefore seems necessary 

 for drawing attention to some of the more salient features of this 

 interesting district. 



Karstland is a term which has been applied by physiographers 

 to a barren and stony limestone district, largely devoid of surface 

 waters. As little sediment results from the denudation of limestone 



1 Mercenier, Ann. Soc. geol. Belg. PubKcations relatives au Congo Beige, 

 etc. Ann. 1912-13, Annexe au Tome xl, 1913. 



