T. BELT ON THE STEPPES OF SOUTHERN RUSSIA. 851 



For 70 miles north-westward from Orel the country is a great 

 undulating plain, everywhere covered with clay ; but unfortunately 

 a snowstorm came on, and covered up the sections before I arrived 

 at the first large boulders from the north. Between Smolensk and 

 Orsha there are many huge northern blocks lying on the surface ; 

 but in consequence of the snow I could not trace their relation to 

 the diluvial clay. Sir Roderick Murchison has, however, done so. 

 In his ' Geology of Russia in Europe,' he has described the northern 

 drift as extending all the way from the German Ocean, on the west, 

 to the White Sea, on the east, a vast zone of country, nearly 2000 

 miles in length, and from 400 to 800 miles in width, more or less 

 covered with drift, with colossal blocks of crystalline rocks, the whole 

 of which have been brought from Scandinavia, Finland, and Lapland. 

 This detritus has been borne southwards in long zones, often sepa- 

 rated from each other by depressions, occasionally of great width, 

 in which few or no blocks are discernible. Hills or slopes, 200 or 

 300 feet high, are covered with blocks, whilst the intervening 

 valleys are free from them. The Valdai hills, which rise to over 

 1100 feet above the sea, are strewn with blocks of granite, gneiss, 

 greenstone, and porphyry, which have come from Finland. Mur- 

 chison traced these blocks as far southward as Voroneje, 700 or 

 800 miles distant from the nearest edge of their parent country. In 

 the southern limits of this zone he found that the materials were re- 

 duced to small size, and mixed with local debris. He traced the drift 

 southward merging into the diluvial clay, and considers the latter a 

 deposit from the same water over which the northern blocks were 

 borne on icebergs. He says, " Extending as far southwards as 

 currents or icebergs would transport them, it is very natural to 

 suppose that where the northern boulders ceased to advance, the 

 bottom of the then sea, remote from any disturbing force, would 

 become covered with fine silt or mud "*. 



Whilst northward the diluvial clay merges into the northern drift, 

 south-westward it bears the same relation to the loess of the valley 

 of the Danube. Thus, if instead of going eastward from Balta, to 

 which place from Karkov I have traced the diluvial clay without 

 break, we go southward, we may follow it, again without break, to 

 Odessa, where it occupies the same position as at Taganrog, and 

 contains the remains of the Mammoth at its base. South-westward 

 from Odessa it wraps round the end of the Carpathians into the 

 valley of the Danube. Admiral Spratt, in his well-known papers, 

 has described the steppes of Wallachia, Bessarabia, and Moldavia, as 

 rising in a gentle slope northwards from the Danube, and ascribes 

 their smooth and level character to the hollows of the older 

 denuded surface having been filled up. by the drift-deposit. He 

 figures a section near Bolgrod, showing that the older beds (which, 

 from their fossils, belong to the Congerian formation) have been 

 denuded, and afterwards covered up with diluvial clay, just as 

 around the Sea of Azof. He found the same characters in the 

 deposits of the steppe at Galatz and near Ibrail, as well as more in 

 * See op. tit pp. 510, 513, 519, 524, and 562. 



