Monday, August 11, 2008

Narragansett Bay 1777



A Topographical CHART of the
BAY of NARRAGANSET in the Province of NEW ENGLAND.
with the ISLES contained therein, among which
RHODE ISLAND and CONNONICUT
have been particularly SURVEYED.
Shewing the true position & bearings of the Banks, Shoals, Rocks &c, as likewise the Soundings:
To which have been added the several Works & Batteries raised by the Americans.
Taken by Order of the PRINCIPAL FARMERS on Rhode Island.
By CHARLES BLASKOWITZ.
Engraved & Printed for WM. FADEN, Charing Cross, as the Act directs, July 22d. 1777.

This early chart of Narragansett Bay was apparently commissioned by the principal farmers of Rhode Island in order to provide the British with military intelligence about the navigation of the bay, and also "the several works and batteries raised by the Americans".

Hmmm. Not very patriotic of them, eh?


The chart claims to show "the true position & bearings of the Banks, Shoals, Rocks &c" but there's one thing that worries me about that claim. If I look out of my window over Mount Hope Bay, the most prominent feature in the middle of the bay is Spar Island, a small flat-topped low island, visible at all states of the tide except the highest, and surrounded by shoals. But Spar Island is not marked on the Blaskowitz chart.

However, Spar Island is marked on the 1861 US Coastal Survey chart of Mount Hope Bay, an original of which hangs in my dining room. So what gives? Was the island created by some geological event between 1777 and 1861? Or was Blaskowitz simply guessing when he came to draw that part of his chart?

10 comments:

Steve in Baltimore said...

Don't know about Spar Island, but I noticed that Wickford was then Updyke's Harbour, and that Quonset point has lost a few syllables since then.

tillerman said...

Well spotted Steve. You kind of expect place names to change and evolve over the centuries, and I may write another post one day about some of the old names on that map (some of which make more sense IMHO than the current names).

But missing a whole island!!!!!

O Docker said...

Maybe some waterological event?

That close to a river mouth, it may have just silted in over 80 years, no?

We've lived close to the American River for about 20 years now, and have watched small islets come and go in that time.

David said...

Or maybe those farmers were more patriotic than you think and were engaging in counterintelligence. I wonder how many English ships went aground there as a result.

tillerman said...

O docker and David, I've wondered about both of your theories myself.

If Spar Island were just a sandbar I can understand how it might come and go, and even move. But there are also what look like rocks visible close to the island at low tide so it's not just sand.

I've also wondered if it's some human artifact. Maybe silt around a shipwreck? Some illegal dumping?

The Google isn't much help either. Wikipedia has a description of its height in relation to the tide that I can see with my own eyes is incorrect, and even places it the wrong side of the Massachusetts/ Rhode Island state line!

O Docker said...

Just going by the chart, it looks like a likely spot for a boneyard.

Maybe that explains 'Spar'?

tillerman said...

I read somewhere that Spar is actually a corruption of Sparrow, because as an uninhabited island it's actually a favorite spot for birds.

Carol Anne said...

I can think of several explanations:

1. As has been suggested, the creators of this map were into counterintelligence and purposely put inaccuracies into the map in order to mislead the British.

2. Cartographers in 1777 were not as careful or "scientific" as cartographers in 1861, and so their maps weren't as accurate. This could be compounded if the 1777 cartographer were less diligent or competent than most.

3. The island may have come into existence between 1777 and 1861, either through human activity such as dumping dredging spoils or through natural action such as river delta deposits.

4. Between 1777 and 1861, the level of the land relative to the water changed, either through the land being uplifted (geologically impossible, given the short time frame, absent major seismic events) or through the water level falling. If that's the case, then global warming, by melting polar ice caps and raising sea levels, will restore conditions to what they were.

I strongly favor explanation #2, although #1 and #3 are reasonably likely as well.

Tillerman said...

My guess is that the surveyor made a cursory swing through Mount Hope Bay at or near high tide, took a few soundings, and never even saw Spar Island.

From my house high above the bay the island is almost always visible. But it's so low that I can believe that someone just sailing around the south half of the bay would never see it. Which of course is why it's so important that it is marked on charts.

Anonymous said...

I believe Spar Island was a dredge spoil island built in the past by the US Army Corps for disposal of clean dredged sediments during maintenance of the Fall River and Brayton Point ship channels into Mount Hops Bay, so it was likely not in existence in the earlier maps.

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