The
Bank, the Bay, the Gulf
and the Sanctuary
|
This
image was developed by the U.S. Geological
Survey using computer visualization software
to turn bathymetric maps into a three-dimensional image.
Click on picture for bigger version.
|
Between
Cape Ann and Cape Cod, in the southwest corner of the Gulf of
Maine, is Massachusetts Bay. The bay's most prominent submerged
feature is the kidney-shaped plateau called Stellwagen Bank, which
lies at the bay's eastern edge. Stellwagen Bank is a shallow,
primarily sandy feature, curving in a southeast to northwest direction
for 19 miles. It is roughly 6 miles across at its widest point
at the southern end. Water depths over and around the bank range
from 65 feet on the southwest corner to depths of about 600 feet
in deep passages to the northeast. Massachusetts Basin on the
western side of the sanctuary levels off at about 300 feet in
depth, while the top of the bank averages about 100 to 120 feet.
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. From the sanctuary's Scituate-based headquarters, the distance is approximately 11 miles.
The
sanctuary boundary occurs entirely within federal waters (beyond
the three-mile limit of commonwealth of Massachusetts 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.
The Sanctuary boundary is marked by the following coordinates, which indicate the northeast, southeast, southwest, west-northwest, and north-northwest points: 42_45'59.83"N x 70_13'01.77"W (NE); 42_05'35.51"N x 70_02'08.14"W (SE); 42_07'44.89"N x 70_28'15.44"W (SW); 42_32'53.52"N x 70_35'52.38"W (WNW); and 42_39'04.08"N x 70_30'11.29"(W) (NNW).
|