150 
southern end of the main ridge, on the east side and quite close 
to the water that the potholes occur. The most southerly and 
most perfect holes are on the north side of a slight indentation 
of the rocky shore and may be readily found when the tide is 
out (Fig. 21). Of the lowest and best preserved of these 
(No. 1) the bottom is still intact and perfect, holding water to 
a depth of 21 inches and having a well-defined rim just at the 
surface of the water. The diameter at the rim is 254 inches; 
below the rim, 30 inches. Above this rim the whole southern 
side of the hole is wanting; but on the northern side the rock 
is smoothly concave and the characteristics of the pothole are 
plainly discernible for a height of four feet, with a breadth of from 
three to four feet, making the total depth about six feet. The 
whole has the appearance of a large, imperfect *or one-sided 
pothole with a smaller and perfect pothole in the bottom of it. 
Exterior to this pothole, the tide sinks below the level of its 
bottom, but at high tide all is covered. 
The second pothole has its bottom three and one half feet 
above that of No. 1; and their centers are three feet apart hori- 
zontally. The whole southern side of this hole (No. 2) is 
wanting and water can now stand in it only to the depth of 
about two inches. Above the bottom, the granite is smoothly 
concaved for a breadth of three feet and a height of five feet; 
and this hole, when entire, was evidently about as large as the 
first. "The slope of what remains of the walls of these holes 
shows, apparently, that the flow of water over the rocks was 
from the west and northwest. Of the third pothole there is 
but little to be said, except that it is small and shallow. It is 
about five feet above the bottom of No. 2, still in a northwest 
direction ; and there may be traced from it in the same general 
direction а narrow water-worn channel about six feet in length. 
The high-tide mark is about midway between the second and 
third potholes. 
It is quite obvious that these potholes were once entire. 
Their sharply-defined vettical edges are seen to coincide with 
