Tlte Karstlands of Western Yugoslavia. 395 



of the Ohio in Kentucky and Southern Indiana, where the 

 labyrinthine Mammoth Cave, containing a system of lakes and 

 streams at varying levels, constitutes the most remarkable instance 

 of underground drainage that has yet been discovered. 



Extent op the Illyrian Karstlands. 



The actual limits of the Illyrian karstlands can be drawn with 

 considerable precision. From the eastern end of the plains of 

 Lombardy, they extend as a broad band through most of Western 

 Slovenia, and from the coast at Trieste they reach nearly as far 

 inland as Ljubljana (or Laibach). The Julian Alps limit the true 

 karst to the north, the valleys of the Idria and the Sora forming a 

 fairly precise boundary between two distinctive types of landscape. 

 In Western Croatia the karst extends from the coast to the edge 

 of the Save plain, while it also includes practically the whole of 

 Istria, Dalmatia, Herzegovina, and much of Western Bosnia. In 

 Montenegro two diverse types of land forms are met with. Thus 

 the country to the west of the Zeta valley constitutes a barren 

 karstland, while to the east in the region known as the Brda a typical 

 upland landscape occurs, thickly wooded and witb perennial streams 

 of considerable volume. 



The southern limit of the Illyrian karstlands is formed by the 

 Northern Albanian Alps, which consist in the main of massive 

 Cretaceous dolomites, and rise abruptly to over 10,000 feet above 

 sea-level. To the Southern Slavs they are appropriately known as 

 the Prokletije Planina (or Accursed Mountains), a very apt reference 

 to their barren karst-like nature. 



Geological Structure. •• 

 The karstlands consist predominantly of Triassic, Cretaceous, and 

 older Tertiary limestones. The oldest rocks met with in the area are 

 the Upper Carboniferous limestones, sandstones, and breccias, which 

 form small inliers around Delnice (or Petrova Gora) in the Kapela 

 Mountains, and also around Budua and Castel Lastua to the 

 immediate south of the Gulf of Cattaro. Broadly speaking, the karst 

 may be subdivided geologically into two main parallel belts ; a 

 coastal strip in which Cretaceous and Tertiary limestones pre- 

 dominate, while to the east of a line drawn from Tolmino in the 

 upper Isonzo valley, through Adelsberg, along the foot of the 

 Velebit range and continued southwards past Knin and Mostar to 

 the base of the Durmitor range in Montenegro, the massive Triassic 

 limestones underlie most of the region. These Triassic rocks consist 

 principally of fossiliferous limestones and dolomites belonging to the 

 " open sea " Alpine type, while the Cretaceous formation includes 

 massive dolom,ites, and limestones characterized by the abundance 

 of Hippurites and Rudistes. The considerable alteration these beds 

 have undergone renders their precise correlation with other areas 

 a, matter of considerable difficulty. 



