4JG Professor Sedgwick and Mr. Murchison on the 



those above alluded to. If any of them have been produced by this second 

 mode of action, it cannot be called dilnvium, except by a use of the word 

 which differs from that for vvhicli it was first intended*. 



Again, when the southern regions of Bavaria were lifted above the waters, 

 not only would the Alpine torrents be shot down into the Danube along the 

 inclined planes presented to them, but many lakes and pools must have stag- 

 nated in the hollows presented by the bottom of the old tertiary sea. Of such 

 expanses of stagnant water, many must have disappeared without leaving a 

 trace behind. But of some we see the marks in low, marshy regions at dead 

 levels, on the sides of which we, here and there, find lines of travertino and 

 other indications of the former action of water: and there are still in upper Ba- 

 varia many lakes and marshy tracts in such positions as would be unnatural in 

 any country of which the drainage had commenced in a more ancient period. 



The inevitable effect of water thus pent up must have been the occurrence 

 of great floods, caused by the bursting of the l)arriers, differing only in degree 

 from the debacles before spoken of, and modifying the surface of the country 

 wherever they extended. Of tliis kind of operation there are traces almost 

 innumerable ; and we did not ascend a single rivulet which falls through the 

 south-western parts of Bavaria without remarking one or two, and sometimes 

 three or four parallel terraces, indicating (as in the parallel roads of Glen 

 Roy) the residence of nearly stagnant water at successive levels. The banks 

 of the Lech near Schongau ofler some fine examples of these phenomena, but 

 they are so common that it seems needless to refer to instances. By all these 

 causes combined, aided by the diurnal erosion of the elements, has the surface 

 of the country been modified since the last elevation of the Eastern Alps. 



* We by no moans deny the reality of diluvial operations, when the word diluvial is used in 

 a limited, and not in a hypothetical, sense. Some of the low longitudinal valleys between the 

 secondary and tertiary deposits — the great breaks of continuity in the same system of strata — the 

 round-topped tertiary hills rising several hundred feet above the mean level of the country — the 

 irregular masses of transported materials, at high elevations, and not along the line of any river 

 drainage — these phenomena we attribute, not to the ordinary erosion of rivers however long 

 continued, but to the action of the retiring waters at the last period of elevation, or to great 

 debacles which soon followed them. By the same kind of action we would explain some of the 

 great erosions near the banks of the Danube. Thus, at the height of several hundred feet above 

 its left bank near Ulm, we find patches of a thick lacustrine deposit sticking on the sides of the 

 secondary hills ; and a precisely similar deposit caps some hills, on the Bavarian side, further 

 down the river, and several miles from its right bank. The lacustrine rocks were probably once 

 continuous, forming a part of an extensive formation which has been breached through, and in a 

 great measure carried off, by denuding currents. 



