THE TRAVELS OF THE UNDERGROUND WATER 187 



Karst region east of the Adriatic Sea, similar features are devel- 

 oped, but upon a grander scale, and certain additional forms are 



encountered. In place of 



the sink or swallow hole, 



there appears the " karst 



funnel " or doline, a deep, 



bowl-shaped depression 



having a flat bottom. 



Such funnels may be 30 



to 3000 feet across and 



from 6 to 300 feet in depth 



(Fig. 196). Though in 



one or two instances 



known to be the result 



of the break down of 



cavern roofs (Fig. 197), 



yet like the swallow holes 



of other regions these 



larger funnels appear gen- 

 erally to be the work of 



solution by the descending waters. Where they have been opened 



in artificial cuttings along railroads or in mines, the original rock 



is found intact at the bottom, with 

 small crevices only going down to 

 lower levels. Over the bottoms of 

 the dolines there is spread a layer 

 of fertile red clay, the terra rossa, 

 like that which is obtained as a 

 residue when a fragment of the 

 limestone has been dissolved in 

 laboratory experiments. 



A desert from the destruction of 

 forests. Between the dolines 



FIG. 196. Map of the dolines of the Karst re- 

 gion near Divaca. 



FIG. 197. Cross section of the do- 

 line formed by inbreak of a cavern 

 roof. The Stara Apnenka doline 

 in Carinthia (after Martel). 



s 



found a veritable desert with jutting limestone angles and little 

 if any vegetation. The water which falls upon the surface either 

 runs off quickly or goes down to the subterranean caverns by which 

 so much of the country is undermined. Hence it is that the gar- 

 dens which furnish the sustenance for the scattered population 

 are all included within the narrow limits of the doline bottoms. 



