GLACIAL EROSION IN LONGITUDINAL VALLEYS 725 
removal of the overlying formations is ice, but on this heading too 
little field work has been done to warrant any definite conclusions. 
As to the folds in question, it is obvious that they are not due to 
buckling. 
Mr. Campbell establishes the competency of joint expansion due 
to weathering to produce folds in certain strata. His figures and 
es 
i pe 
Fic. 2.—Subjacent strata folded by glacier ice. Area shown is northeast of Locke, 
N. Y. 
explanation impress the symmetry of such folds. For this reason 
the theory of weathering cannot apply to our cases. 
There are several reasons that point to glacial ice as the agent 
involved in the present folding. In Fig. 2 the fold is overturned in 
the direction of ice-motion. This fold lies slightly off the line of the 
valley segment north of Moravia. Striae to the north and east of 
the fold, within a radius of one and one-half miles, give an average 
direction of S. 31°-E.,’ the extremes being S. 18°, and 48° E. Owing 
t Only magnetic readings are given in this paper. 
