184 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
There can be no question that the sand dunes of this locality have 
been formed in the past when conditions were very different from those 
of the present ; for now the entire coast line in this region is granite 
rock without the vestige of a beach to supply the sand. Nor is there 
any interior supply; it seems to have come from the seaward side. 
It might, of course, be assumed that when the waves began their work 
after the ice retreated, they stripped the soil from the rock and formed 
beaches which have since been destroyed, leaving no evidence of their 
existence, and that all this happened while the land was at its present 
elevation. 
This explanation seems inadequate for at least two reasons. In the 
first place, the presence of the rounded pebbles suggests the presence of 
the sea at higher level; and, in the second place, the present outline of 
the coast is not of such a form as to lead to the development of beaches. 
It is altogether too straight a stretch of granite; but if the land were 
depressed the coast line would become very much more irregular, and 
sand beaches might well develop in the bays. With the disappearance 
of the waves from the land through elevation, the beach sands might well 
have been blown about, forming sand dunes. 
While by itself this area of sand dunes, although strongly suggestive, 
could not be deemed conclusive evidence of former depression of the 
land, when taken in connection with the other evidences of depression it 
constitutes a link in the chain of evidence of such importance that it 
must be considered. 
Delta Deposits. — Since there are no large streams on Cape Ann, well- 
developed deltas would not be expected. Only one perfectly defined 
delta was found on the Cape. It is located near the road from Gloucester 
to Rockport, and is best seen where a branch road extends from the one 
just mentioned down to Good Harbor Beach (F, Plate1). At this point 
the delta is bisected by a small stream flowing from the direction of Cape 
Pond. The crest of the delta is about 50 feet above sea level, and it 
has a length of about one-half mile, with a width of a quarter of a mile. 
Along the road to Good Harbor Beach a cut reveals the internal struc- 
ture of the delta to the depth of 25 feet, showing distinctly cross- 
bedded sands and gravels dipping seaward and overlain by horizontal 
surface beds of gravel. The crest is remarkably level, though with a 
gentle seaward slope ; and upon its surface, in several places, are linear 
indentations, evidently channel ways. It faces away from the ice, and 
toward the open sea, and therefore there is no reason for considering it 
a sandplain in an enclosed valley dammed by the ice, 
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