292 
Г. Armaschewsky. 
perficial deposits of the basins of tlie Rhine, Danube and some other large rivers drai- 
ning the Alps, and which extend down tlie Rliiue into tlie Low Countries, and were 
once perliaps continuous with other of like composition in the nortli of France. No 
doubt it is true that in every country, and at ail geological periods, rivers hâve been 
depositing fine loam on tlieir inundated plains in the manner explained above, where 
the Nile mud was spoken of. This mud of the plains of Egypt, according to Professor 
Bischoff’s Chemical analysis, agréés closely in composition with the loess of the Rhine. 
I hâve also shown, when speaking of the fossil man of Natchez, how identical in mi¬ 
nerai character, and in the généra of its terrestrial and amphibious shells, is the an- 
cient fluviatile loam of tlie Mississippi with the loess of the Rhine. But granting that 
loam presenting the same aspect lias originated at different times and in distinct liy- 
drographical basins, it is nevertheless true that, during the glacial period, the Alps 
were a great centre of dispersion, not only of erratics, as we hâve seen in the last 
chapter, and of gravel, which was carried farther than the erratics, but also of very 
fine mud, which was transported to still greater distances and in greater volume down 
the principal ri ver-courses between the mountains and the sea. The position of the 
loess between Basle and Bonn is such as to imply that the great valley of the Rhine 
had already acquired its présent sliape, and in some places, perliaps more than its 
actual depth and widtli, previously to the time when it was gradually filled up to a 
great extent with fine loam. The greater part of this loam lias been since removed, 
so that a fringe only of the deposits is now left on the flanks of the boundary hills, 
or occasionally some outliers in the middle of the great plain of the Rhine where it 
expands in width 1 )“. 
Es ist also in Lyells Ausführungen ausdrücklich gesagt, erstens, dass der Lôss 
sich in den Flüssen abgelagert hat, zweitens, dass er nacli Ausfüllung der Flussthaler 
soweit wieder hinausgeschwemmt worden ist, dass er nur an den Thalflanken erhalten 
blieb, und drittens, dass das Material, woraus der Lôss entstanden ist, noch bevor es 
in die Flüsse gelangte, durch die Thatigkeit von Gletschern vorbereitet worden ist, 
indem sie bei ihrem Vorrücken eine unter Anderem aus sehr kleinen Quarzkornern und 
Thonpartikeln, denen Lyell die Bezeichnung Gletscherschlamm beilegte, bestehende Grund- 
morane bildeten. Diese von Lyell am eingehendsten clargelegten Anschauungen in Bc- 
treff der Entstehung des Loss, gewinnen um so grôssere Bedeutung, als sie in be- 
tràchtlichem Maasse den Gelehrten, die sich in der Folge mit dem besprochenen Ge- 
genstande befassten, als Ausgangspunkt gedient haben. So legen einige Geologen (Uh- 
lig 2 ), Jentsch 3 ), Credner 4 ), Benecke und Cohen 5 ) bei der Erklarung der Lôss- 
9 Lyell, The geol. evid. of the antiqu. of man, 2 ed. 1893, p. 324—326. 
-) Jahrb. d. k. k. geol. Reichsanst. 1884, S. 212. 
3 ) Ueb. d. Loss, Ztschr. f. d. ges. Naturw. 1872, B. 2. 
4 ) Ueb. Lossablag. in d. Zschopau, N. J. 1876, S. 14. 
5 ) Geogn. Bescbr. d. Umg. v. Heidelberg, 1881, S. 572. 
/ 
