HO IV THE SOIL CAME. 35 



where it is about one thousand feet deep and about one 

 mile wide, moved towards the sea forty feet per day on 

 the average, in the month of August, 1886.* 



The grinding of rock into flour by a movement of forty 

 feet per day under such a pressure as one thousand feet 

 of ice would result in a huge grist if continued for several 

 thousand years, as was undoubtedly the case at Cohasset. 



All the soil which existed in the town before the ice 

 period must have been pushed into the ocean to the 

 south, Professor Crosby assures us ; but soil enough was 

 being made by the glacier in places to the north of us 

 that was destined to clothe our ledges which the same 

 glacier had stripped. Our hills of hardpan are a witness of 

 this reimbursement. 



But before relating the events of this reimbursement, 

 there is to be noted a long period of scouring which the 

 solid ledges nowadays tell to eyes that will observe. 



The earth and stones, frozen to the bottom of the 

 glacier as they were sliding over the solid rock, made 

 grooves and scratches, much as a piece of sandpaper 

 does upon smooth wood. 



Uphill along every stoss slope of rock the sheet was 

 pushed, and then bending down again it slowly conformed 

 to the inequalities of the rock, rounding off edges and 

 tearing off the lee sides. At the head of Depot Court, 

 where the ledge toes the east side of Main Street, the 

 horizontal marks can be seen by any passer daily, showing 

 how the under side of the glacier bent around that ledge, 

 scrubbing it clean and leaving the scratches. The marks 

 at this particular place have been preserved by the dirt 

 which undoubtedly laid against it for thousands of years 

 before white men came. Wherever the rock has been ex- 

 posed to the weather since the glacier melted, all the 

 scratches have been worn off by the destructive elements. 

 But the appearance that all our ledges must have had 



* Professor Wright's Ice Age in North America, p. 51. 



