118 
MOUTH IN A NEARLY VERTICAL CLIFF. 
country of Blankenburg; its relative position to the nearest river is 
low when compared with Scharzfeld, being at an elevation of about 
100 feet above the bed of the Bode; this, however, is sufficient to 
assure us, that it is quite impossible to attribute the pebbles and 
mud within this cave to any floods of that river, which could not rise 
ten feet without destroying the adjacent village of Rubeland. Above 
this village is seen the present entrance of the cave, in a nearly per¬ 
pendicular cliff, which forms the left side of a deep gorge, through 
which the river runs, and which is similar to that through which the 
Avon passes at Clifton. (See Plate XV. l.) The breadth of this gorge 
varies from 100 to 300 feet, its depth is about 150; the rocks on both 
sides of it are nearly precipitous. In the drawing the scale is falsified 
as to breadth, for the sake of getting room*. 
The present entrance (see Plate XV.) is by the aperture a into a 
low flat cavern, 15 feet broad, and five feet high; the outer extremity 
of which is in the truncated face of the cliff, whilst within, it descends 
rapidly to the broad and lofty chamber b. The form of this chamber 
is irregularly oblong, varying from 30 to 50 feet in diameter, and 
from 10 to 20 in height, and affording some of the most grand and 
picturesque features of cave scenery. The floor of this cave resembles 
in all its circumstances that of the great cave at Scharzfeld, with the 
addition of several large masses of rock (see o, o) that have fallen 
* This gorge is simply a valley of denudation, produced (like hundreds which I 
could mention in compact limestone countries) by the force of the diluvian waters. The 
dotted line n (Plate XV.) represents the manner in which the two sides were probably 
connected before the excavation of the gorge, and m the probable continuity of the pre¬ 
sent mouth of the cave a to the then existing surface. As I shall hereafter consider the 
evidence geology affords of the formation of such valleys by the diluvian waters, I at pre¬ 
sent beg those of my readers to whom this subject is new to allow the fact to be assumed 
in the case immediately before us. 
