The Bank, the Bay, the Gulf
and the Sanctuary
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This
image was developed by the U.S. Geological
Survey
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to
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image. Click on picture for bigger version.
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Between Cape Ann
and Cape Cod, in the southwest corner of the Gulf of Maine, is Massachusetts
Bay, 75% enclosed by land. The bay's most prominent submarine feature
is Stellwagen Bank, which lies at the bay's eastern edge and partially
blocks its mouth. Stellwagen Bank is a shallow, glacially-deposited,
primarily sandy feature, curving in a southeast to northwest direction
for 18.75 miles. It is roughly 6.25 miles across at its widest point
at the southern end. Water depths over and around the bank range from
65 feet to more than 300 feet. Seaward of the bank, the seafloor slopes
to depths of 600 feet or more.
Stellwagen Bank
is the centerpiece of the Stellwagen Bank National Marine Sanctuary,
which encompasses a total of 638 square nautical miles, or 842 square
miles. The sanctuary also includes all of Tillies Bank (situated to
the northeast of Stellwagen Bank) and southern portions of Jeffreys
Ledge (situated to the north). The western boundary line of the sanctuary
is approximately 25 miles east of Boston; the southern boundary is three
miles from Provincetown while the northwestern boundary is three miles
from Gloucester.
The sanctuary boundary
occurs entirely within Federal waters (beyond the three-mile limit of
Commonwealth jurisdiction). The southern border follows a line tangential
to the seaward limit of Commonwealth jurisdiction adjacent to the Commonwealth-designated
Cape Cod Bay Ocean Sanctuary; and is also tangential to waters designated
by the Commonwealth as the Cape Cod Ocean Sanctuary. The northwest border
of the sanctuary coincides with the Commonwealth-designated North Shore
Ocean Sanctuary.
