724 FRANK CARNEY 
overlain by about two feet of drift and rubble, but this horizon very 
likely consisted formerly of ground moraine which was removed in 
the process of quarrying. 
Fig. 3 is of a fold at station 3, directly north of Moravia. This 
photograph was taken a few days after an unusually heavy storm 
which caused many slight streams to leave their former courses, thus 
exposing fresh sections in the tile. The area shown is on the north 
side of such a recent cut. The axis of the fold inclines 36°, the section 
being approximately east-west. The fold is turned up the slope or 
against gravity; it consists of thin bedded shale and sandy layers 
amounting to about 18 inches. ‘This is overlain by three to four 
feet of ground moraine, very compact, and is underlain by a hard 
layer of sandstone over which the stream is flowing. 
HOW THESE FOLDS WERE PRODUCED 
As to the causes that may have produced these folds shown in 
Figs. 2 and 3, which have been selected from a series of photographs 
of which these are typical: Does the frost theory explain this work ? 
The probable type of a fold caused by freezing is more symmetrical, 
and, as shown by Sardeson, has in its upper horizon a weathered 
zone in which the rock has more thoroughly disintegrated, the section 
blending into less residual material. Fig. 3, however, is obviously 
below the normal frost line for this climate; while Fig. 2 doubtless 
shows an area that is subject to frost, as the upper part of the apex 
of the fold in Fig. 2 very likely has been slightly altered through the 
influence of frost work. In any event, however, frost folds would 
be more symmetrical than these. Consequently the frost theory does 
not seem to apply. 
Little need be said concerning the theory of creep, since Fig. 3 is 
obviously a fold tilted against gravity, while Fig. 2 is a fold along the 
contour of the slope. It does not seem probable in any event that a 
fold due to creep would ever be overturned as Fig. 2 is. 
Elsewhere in the Moravia Quadrangle folds possibly due to 
buckling induced by the removal of overlying strata have been 
observed, but these cases are always symmetrical in relation to the 
axis of the fold, and apparently show the effects of rather speedy 
giving away to certain stresses. The agent probably involved in the 
