... The history of this most dangerous and fatal shoal is startling. Situated in mid-ocean; having, in low ebbs, scarcely a foot of water; in a region proverbial for its heavy swell; rising, at times, without a moment's warning; the dread of all mariners, and the grave of thousands ....   
<p>--William Mitchell  
</p>
Uncommon, highly significant, and often under-appreciated, this is 1848 map is the first U.S. Coast Survey chart to depict the shoals off Nantucket.  Though the unpredictable waters off Nantucket were long a nemesis to sailing vessels on the important London – New York shipping routes, they had never been properly charted.  The harsh conditions, including rapid unexpected swells and frequent heavy fog, contrived to make the hydrographic survey of the hazards south of Nantucket one of the most dangerous and challenging projects of the early coast survey.    The first survey party to tackle this area was lead by the indomitable Lieutenant Commanding Charles H. Davis.  Starting at Old South Shoal, a known danger, Davis worked his way southward and soon discovered “New South Shoal”, which was later renamed “Davis Shoal” in his honor.  Working seasonally, it took the Coast Survey to 1853, fully seven years, to complete the survey of the Old South Shoal and Davis’ Shoal.    The outline map of Nantucket, appearing in the upper left hand quadrant, is based upon a map prepared by William Mitchell, a Nantucket local and life long friend of Bache.  This outline of map of Nantucket would continue to grace the upper left corner of the U.S. Coast Survey “Davis Shoal” sheets until the late 1850s.  Prepared by Charles H. Davis under the supervision of A. D. Bache for the 1847 edition of the  Superintendent’s Report .
<div class="fn value">
<a href="https://en.wikipedia.org/wiki/United_States_Coast_Survey" class="extiw" title="en:United States Coast Survey">United States Coast Survey</a></div>
1846 (dated)
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