GLACIAL DRIFT. 265 
hood of Pawtuckaway mountain, and found a very formidable array of 
giant fragments superior to anything else described elsewhere. The 
celebrated Pierre-a-bot of the Jura contains about 40,000 cubic feet, 
weighing 3,000 tons; the Green Mountain Giant of Whitingham, Ver- 
mont, has the same cubical contents; the one formerly existing at Fall 
River, Mass., now destroyed, is estimated to have weighed 5,400 tons. 
The Churchill rock of Nottingham, shown in a heliotype at the begin- 
ning of this chapter, measures 62 feet long by 40 wide, and is estimated 
at 40 feet high. Making liberal allowances for irregularities in its 
dimensions, it contains over 75,000 cubic feet, weighs 6,000 tons, and 
is therefore nearly double the size of the Jurassic and Vermont exam- 
ples. Bingham’s rock at Smuggler’s notch in Vermont is larger, but is 
so connected with a ledge as not to be properly esteemed an erratic. 
The Swiss example has been transported much farther than either of 
the New England boulders. 
Churchill rock is on the south side of north Pawtuckaway. It lies in 
a valley not shown on our map by contours, starting at the middle of the 
Deerfield and Nottingham line where it passes over this peak, and point- 
ing east to Round pond, made a part of Pawtuckaway pond upon the 
county map. This valley is half a mile long, and displays a very remark- 
able lot of large boulders and moraines. The commencement of the 
valley is a narrow notch in the sienite of the mountain, full 200 feet deep 
and narrow. The boulders seem to have been detached from the cliffs on 
either side of the notch, and then transported by the ice, perhaps, or local 
glacier, eastwardly. Within a few rods of the starting-point are several 
large blocks, worthy of special measurement anywhere except in their 
company. About an eighth of a mile down, too far to allow of their 
accumulation by gravity, are six large boulders close together, each one 
averaging 30,000-35,000 cubic feet. A little beyond them is Chase 
rock, 40 feet long, 40 feet high, and 30 feet wide. About a quarter of a 
mile or a little less from the starting-point is Churchill rock, and close 
by it two others, one estimated as equal to 30 feet in each direction,— 
27,000 cubic feet,—and the other ten feet longer, with the same breadth 
and height, or 36,000 cubit feet. On climbing the mountain north of 
Churchill rock, some large blocks are seen, which have been severed 
from connection with the ledge; one of them 50 feet long, slab-like in 
