688 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



the till, it is after a few nudulatious thrown into a series of shai-]) zigzags 

 or short distinct faults, and the layers thus brought into a vertical position 

 together or bent over southward are then dragged along beneath the ice, 

 running a few feet parallel to it and blending together into a confused 

 layer a foot or two thick, in which no structure is visible. On the opposite 

 side, after the last cutting, the appearance was very similar, except that 

 the layers were thrown into still greater confusion, and for 4 rods all the 

 upper half of the sand, 13 feet in thickness, had been pushed 15 or 20 

 feet southward, the layers now standing on their heads and thrown into 

 folds as complex as the sutures of an ammonite; and farther on the whole 

 mass has been wedged in between the layers of the sands in advance, heav- 

 ing them up and occupying in a contorted mass a great triangular space 

 beneath them. The till rides over the whole, and every layer of the con- 

 torted mass as it comes up from below, as well as of that thrown up by the 

 iindertluust portion, bends over southward beneath it as the smoke curls 

 over the cliimney edge in a strong wind. As the till contuiues southward 

 over the sands it moves parallel with their lamination and disturbs them very 

 little, and at last, as it thickens downward, it cuts across them at a low ang-le, 

 and the layers just below run on continuously and .show no signs of any 

 eflfect from the ice. 



Where the fom-th till rising o^■er the sands is cut otf by erosion it is 

 already largely composed of the contorted clays. 



Southward, across the ravine, the surface occupied by the ice sinks 

 into a gentle depression and rises over the pink sands and goes down 

 below the level of the cutting near its south end. It is a siu'face and noth- 

 ing more, and in this long distance south of the brook ravine, as well as in 

 the equally long distance north of the drumlin, no trace of till is found upon 

 it. Only in the remaining space, from the drumlin south, the stratum of till 

 is carried forward along this plane, and it is unfortunate that its ending is 

 not to be observed in a satisfactory way, owing to erosion. It is, therefore, 

 not strictly proved that this plane is continuous, but the identity of the beds 

 north and south of the drumlin makes this highly probal)le, and an insj^ec- 

 tion of the section will show it to be the only simple siijaposition, any other 

 requiring an additional recession and advance of the ice. 



Everywhere below this plane the clays are variously contorted, as in 

 the reach north of the drumlin; often clay and sand are curiously molded 



