ANCIENT GLACIERS. 69 



numerable glacial grooves and scratches upon the rocks 

 which can be found on almost any freshly uncovered sur- 

 face. In New England the direction of these grooves is 

 ordinarily a little east of south. Upon the east coast of 

 Massachusetts and New Hampshire the scratches trend 

 much more to the east than they do over most of the in- 

 terior. This is as it should be on the glacial theory, since 

 the ice would naturally move outwards in the line of least 

 resistance, which would, of course, be towards the open sea 

 wherever that is near. In the interior of New England 

 the scratches upon the rocks indicate a more southerly 

 movement in the Connecticut Valley than upon the 

 mountains in the western part of Massachusetts. This 

 also is as it should be upon the glacial theory. The 

 scratches upon the mountains were made when the ice 

 was at its greatest depth and when it moved over the 

 country in comparative disregard of minor irregularities 

 of surface, while in the valleys, at least in the later por- 

 tion of the Ice age, the movement would be obstructed 

 except in one direction. In the interpretation of the 

 glacial grooves and scratches it should be borne in mind 

 that they often represent the work done during the clos- 

 ing stages of the period. Just as the last shove of the 

 carpenter's plane removes the marks of the previous 

 work, so the last rasping of a glacial movement wears 

 away the surfaces which have been previously polished 

 and striated. 



In various places of New England it is interesting as 

 well as instructive to trace the direction of the ice-move- 

 ment by the distribution of boulders. My own atten- 

 tion was early attracted to numerous fragments of gneiss 

 in eastern Massachusetts containing beautiful crystals of 

 feldspar, which proved to be peculiar to the region of 

 Lake Winnepesaukee, a hundred miles to the north, and 

 to a narrow belt stretching thence to the southwestward. 

 In ascending almost any of the lower summits of the 



