230 



EUSSIA IN EUEOPE. 



After leaving the " Wendish Switzerland " through a deep defile, the Livonian 

 Aa enters the lowlands, and turning north-west, now flows directly to the Gulf of 

 Kiga. But the crescent-shaped rivulets and strings of lakelets still partly com- 

 municating with the Dvina show that the Aa itself was also a tributary of the 

 main stream. 



North Livonia offers another curious instance of shifting river beds. The 

 Virz-jarv, or " White Lake," occupies an area of about 106 square miles in 

 the centre of the depression, stretching south of the Esthonian plateau and 

 declivities. Throuo-h a valley in the north-east corner of this lacustrine basin 



Fig. 111. — Shifting Delta of the Dvina and Aa Hivers. 

 Scale 1 : 800,000. 



r.of c 



Depth mider 80 Feet. 



80 Feet and upwards. 

 .^ 10 Miles. 



the Embach escapes to Lake Peipus and the Narova. But another valley in the 

 north-west corner, evidently a western continuation of that of the Embach, runs 

 to the depression through which now flows the Fellin to the Pernau and Gulf of 

 Riga. Esthonia was thus formerly separated by a continuous stream from the 

 mainland. But, in consequence of the upheaval now going on, the outflow of the 

 Virz-jarv westwards to the Gulf of Riga has been interrupted, and the lake 

 itself is now 112 feet above sea-level. There w\as doubtless a time when 

 Esthonia was an island, like those of Osel, Dago, Worms, Moon, now lying off its 

 west coast between the Gulf of Riga and the Baltic. From their outlines, relief. 



