Pleistocene Geology of Moravia Quadrangle 425 
where beds are so deeply buried this explanation is not applicable. 
The area shown in fig. 26 is below the normal frost line for this 
climate. Fig. 25 gives a section the upper part of which is 
subject to frost; there is evidence here of frost alteration in the 
apex of the fold, but this fold is so unsymmetrical that the frost 
theory cannot apply. 
Folds due to creeping are not uncommon especially in the 
horizons of thin beds. The factor which induces the disturbance 
Fig. 26. This view shows subjacent strata disturbed by the outward or lateral 
motion of an ice-lobe. 
J is gravity. A fold then which is turned in a direction contrary 
to the supposed force of gravity cannot be thus explained. 
In glaciated countries it is very probable that the superficial 
rock horizons when removed by glacial erosion and other methods 
of ice disintegration no longer subject the underlying strata to 
the normal burden of their weight, and in response to this removed 
pressure these underlying horizons doubtless buckle, producing 
a fold. Such folds, however, should always be symmetrical or at 
