152 
= 
hundred feet distant from the others; and it is a little farther 
than the others from the shore, its bottom being about four 
feet above high tide (Fig. 22). "The bottom of this hole, 
which is still entire, so as to hold water to a depth of about one 
foot, is cut in the solid granite at the base of a small scarp. 
It is somewhat oval in form, the horizontal diameters varying 
from two feet ten inches to four feet. The ledge rises abruptly 
nine feet from the margin of the Well and ten feet from its 
bottom ; and the Well itself was probably as deep at least as 
ten feet, the curvature and wearing of the rock clearly showing 
this. The beautifully rounded and water-worn form of the 
granite on the southeast side of the Well, above the water, is a 
plain indication, however, that it has not been entire on this 
side since the water ceased to swirl through it. On the north 
side the concave wall is vertical or slightly overhanging; but 
on the west side the wall is widely flaring, receding upwards in 
such a way as to indicate that the water entered at this point, 
the Well agreeing in this respect with the group of potholes 
(1 to 3). It seems probable that the pothole was entire in its 
early stages ; but as it increased in size the outer or lee wall 
was either worn through or carried: away bodily by the ice, 
after which the rush of water continued long enough to develop 
the graceful contours of its natural exit, as shown jn the 
figure. 
Besides these four potholes, there are other depressions 
which are evidently incipient or embryo potholes. A linear 
group of these may be observed about twenty feet north of, 
and parallel with, the southern series (1 to 3). The upper 
one is shallow, like the bowl of a spoon, about a foot across, 
showing, extending from it, a water-worn channel sloping 
easterly about ten feet to the brink of the ledge, connecting the 
first depression in its course, with two others of similar form ; 
while on a lower surface there is a larger depression just where 
the water from the first might descend. 
Considering the shallowness of the entire portions of all the 
