The universal geography : earth and its inhabitants

, 10230 RUSSIA IN EUROPE.After leaving tho " Wendish Switzerland" tl) rough a deep defile, the LivonianAa enters the lowlands, and turning north-west, now flows directly to the Gulf ofRiga. But the crescent-shaped rivulets and strings of lakelets still partly communicatingwith the Dvina show that the Aa itself was also a tributary of themain stream.North Livonia offers another curious instance of shifting river beds. TheVirz-jiirv, or " White Lake," occupies an area of about 106 square miles inthe centre of the depression, stretching south of the Esthonian plateau anddeclivities. Through a vallev in tho north-east corner of this lacustrine basinFig HI. Shifting Delta of the Dvina and Aa Rivers.Scale 1 : 800,000.[.Of C 85 40Depth under SO Feet.80 Feet and upwards.Miles.the Embach escapes to Lake Teipus and the Narova. But another valley in thenorth-west corner, evidently a western continuation of that of the Embach, runsto the depression through which now flows the Fellin to the Pernau and Gulf ofRiga. Esthonia was thus formerly scjjarated by a continuous stream from themainland. But, in consequence of the upheaval now going on, the outflow of theVirz-jarv westwards to the Gulf of Riga has been interrupted, and the lakeitself is now 112 feet above sea-level. There was doubtless a time whenEsthonia was an island, like those of Osel, Dago, Worms, Moon, now lying off itswest coast between the Gulf of Riga and the Baltic. From their outlines, relief,