3i6 The American Geologist. ^^y- i^*^^- 
feet again — the same hight as the base of the chft on the op- 
posite side — and is marked at this hight by a boulder pavement. 
From here the slope is uniform and gradual for nearly half a 
mile to the water's edge, with no sign of old water levels. This 
long slope is strewn with large and small boulders in great pro- 
fusion. 
A profile across the island from east to west through the 
northern hill is shown in Fig. 4. The line of this profile started 
at a point on the eastern shore where the old beaches below 
forty feet are lost in a strong wave-cut cliff thirty-five feet high 
rising from a few feet above present water level. 
Giant's Tomb island which is situated about six miles north 
of west from Beausoleil island is about four miles long by one 
mile wide. It is named from the appearance of a large flat- 
topped hill near its center which resembles an enormous grave 
when seen from a distance of several miles. This hill, which 
rises to a hight of 172 feet at the highest point measured and 
has a maximum diameter of probably three-fourths of a mile, 
is one of the most prominent features of this portion of the bay, 
and is a familiar landmark visible for miles from any direction. 
It is evidently of glacial origin and its sand, gravel and bould- 
ers have no doubt furnished the material from which the whole 
island and its surrounding shoal have been composed. No 
country rock was found in any part of the island. 
The shoal surrounding the island varies in Avidth from one 
hundred to eight hundred feet. Upon this shoal the water is 
less than six feet in depth, but at the edge of the shoal the 
depth increases abruptly to many times that amount. The shoal 
is in fact a wave-formed terrace or shelf covered at various 
points with sand, gravel and magnificent examples of boulder 
pavement. In other places, more exposed to violent wave ac- 
tion, the covering is of large boulders up to six and eight feet in 
diameter. A fall of ten feet in the water level of the bay would 
probably increase the area of the island by twenty-five per cent 
and uncover a fine example of shore line. 
Several trips across the island showed that the sandy sur- 
face of the eastern side rises gradually from the water to the 
foot of an abrupt rise of from twenty to fifty feet in different 
places, carrying one to the top of the hill. This sandy slope is 
covered with the records of old water levels. Ridges, terraces, 
