920 PROFESSOR J. PRESTWICH ON THE EVIDENCES OF A SUBMERGENCE 
confined to the limits of those valleys, but occurs on the watersheds which separate 
them, as, for example, on the pass above Ham, between the basins of the Somme 
and the Oise, at a height of 184 feet above the sea-level. Not only so, but deposits 
of Loess cover the plateaux between these and other river-valleys of the north of 
France and Belgium which rise to the height of 400 to 650 feet, whilst in central 
France the Loess on the hills and plateaux attains a height of 700 feet, and in the 
neighbourhood of Lyons of some 1300 feet (about 400 metres).* 
But this is far from showing the limits of height which it attains in Central Europe. 
In the upper valleys of the Rhine and Danube it rises to altitudes of not less than 
1500 feet, and even higher in some parts of Central and Eastern Europe. The 
Odenwmld, the Taunus, and other upland tracts, are cloaked with Loess up to a 
considerable height. The Danube and many of its tributaries flow through vast 
tracts of it. Lower Bavaria is thickly coated with Loess, and it attains a great 
develoj)ment in Bohemia, Austria, and Moravia—in the latter country rising to an 
elevation of 1300 feet. It is equally abundant in Hungar}^ Galicia, and Transyl¬ 
vania, and in the valleys of the Carpathians it stretches u]^ to heights of 800 and 
2000 feet. 
That the great rivers of Europe were, during the Glacial period, laden in times of 
flood with fine sediment which they deposited to certain heights in the valleys 
through which they flowed, admits of little doubt. It is the view which, with other 
geologists, I have myself advocated.! It is impossible, however, to suppose that that 
Loess which lies spread in thick sheets over whole countries, covering them as though 
with a mantle, and rising to great heights, can, with the hydrography of those 
countries as it now exists, or as it existed in Glacial times, be the result of any 
ordinary river floods. The whole question is too large to be discussed here, but I 
would draw attention to some of the objections which attend its reference to river 
floods, with the river valleys and the land gradients in the form they now exist. 
To meet the difficulties, two suggestions have been made. The one is that at 
the time of the deposition of the Loess “ the amount of depression and re-elevation in 
the central (mountain) region was considerably in excess of that experienced in the 
lower countries or those nearer the sea, and that the rate of subsidence in the latter 
was never so considerable as to cause submergence or the admission of the sea into 
the interior of the continent by the valleys of the principal rivers. It was 
supposed that the depression might have been at the rate of five feet in a century in 
the mountains, and only as many inches in the same time nearer the coast, and that 
the Loess was accumulated during subsidence and removed during the upheaval of 
the land. But there is nothing to corroborate this view, and even supposing that 
these movements might to some extent have equalized the levels, the height to wliich 
* ‘Bull. Soc. Geol. Franc.,’ 2nd ser., vol. 16, p. 1067. 
t ‘Phil. Trans.,’ 1864, p. 247. 
X ‘ The Antiquity of Man,’ p. 383, 
