The familiar figures of the sailor and Native American made their first appearance in 1686, one year after James (our proprietor) moved up from Duke of York to King James II. After the Revolution, a single adjustment was “officially” made--an eagle replaced the royal crown--but in the process a symbol was lost. Then, in 1915, after decades of loose standards and builders and sculptors taking artistic license with the seal on buildings and monuments throughout the city, the Common Council ordered the history books dug out and a final "once-and-for-all," "this is the real deal" seal was officially promulgated, and the old symbol re-appeared in the process. In fact, the seal's history is rife with one “tempest in a teapot” scandal after another.
First the basics. Let's break down the current, official seal.
The seal is wrapped in a laurel wreath. Most often used as a symbol of victory (to "rest on one's laurels" is to milk past achievements), it's the bay leaf. A more familiar symbolic image may be this...
An eagle, facing and rising towards a sailor, surmounts a hemisphere at the top.
The sailor holds a plummet in his right hand, the Native American holds a bow in his left. Some accounts say the sailor is holding a plumb, a carpenter's tool, but it's actually a lead-lined plummet used for measuring water depths. And just because visuals are fun,
Both figures stand on a laurel branch.
On the rare occasion that the seal gets any press coverage at all, it's usually because of the date at the bottom, which since 1977 has been 1625, a date most agree is meaningless. Over its history, though, the seal has displayed different years depending on whatever hallmark event was fashionable to recognize at the time.
Now for the really interesting history. At the center, a shield is emblazoned with two beaver and two flour barrels in the spaces between the arms of a windmill.
The beaver (their pelts for fur and skin for hats) is most famously associated with New York's economic beginnings under the Dutch. To give you an idea of just how central beaver were in the early economy, the Netherlands-bound ship, the Arms of Amsterdam, delivered the Schagan letter bearing the news of Peter Minuit's purchase of the island in 1626, which also enumerated this cargo:
7,246 Beaver skins
178 1/2 Otter skins
675 Otter skins
48 Mink skins
36 Lynx skins
33 Minx
34 Muskrat skin
The English took over in 1664 and a decade later a "new beaver," so to speak, was found--and just for Manhattan--in the actions of Governor Andros who ordained that all imports be processed through the port of New York. As well, all exports had to be packed, loaded and shipped from New York. With Andros' decree, every community from Albany to Amboy to Hempstead had to send their cattle, pigs, and harvest to New York for export. Flour, though, was the “new beaver.”
"Bolting" flour was the arduous multi-stage process of separating wheat into flour and bran. Apparently New Yorkers were quite adept at it since one of Andros' main arguments for the law was that it was needed to ensure a consistent and high quality product. With bolting, barrel-making became a booming island industry.
Had the decree not come about it’s hard to say how much New York's run up to power would have been affected later on. The Erie Canal stood on the shoulders of previous booms, just as the flour boom stood on the shoulders of the beaver trade. Its benefits to Manhattan were nothing short of mind boggling. Stokes Iconography sums it up from a written complaint lodged by a New Yorker lamenting the 1694 repeal of the pro-Manhattan law. (The "Bolting Act," a term often attributed to the law itself,
When the city enjoyed the bolting monopoly several advantages accrued to this city and province. In 1678, when the bolting began, there were only 343 houses in New York. By 1696, 594 new buildings had been added. This increase is to be attributed to the bolting. The revenue in the years 1678, '79, and '80 did not exceed £2,000; but after that it increased annually until it amounted in 1687 to £5,000.... In 1678, there were three ships, eight sloops and seven boats belonging to this port; in 1694, there were 60 ships, 62 sloops, and 40 boats.... In 1678, not over 400 [beaver] were killed; in 1694, nearly 4,000. Lands were low-priced during those years; since then they have advanced to ten times their value. Of the 983 houses in New York, 600 depend upon bolting.In 16 years the port went from owning 18 seaworthy vessels to 142, mostly due to sifting flour. Andros' laws did for Manhattan what the Erie Canal would do 125 years later: triple the economy in a few years and put Manhattan in the enviable position of middleman. So the flour barrel got its place on the seal.
The windmill's connection to the Dutch is not necessarily a given; when it first appears on the seal we were under English rule, and windmills were popular there, too. But the 1686 seal, when it first appears, was the first seal created by New Yorkers themselves. And since there were many Dutch in positions of authority, and many of them had windmills on their coats-of-arms, it probably does symbolize Dutch heritage. But the best argument can be found in the position of the windmill's arms, they mimic the saltire, or St. Andrew's Cross, and three saltires arranged vertically was the official Dutch emblem.
The evolution of the seal.
1623. The seal of the Province of New Netherland--not specifically New Amsterdam. New Netherland stretched from parts of Connecticut to Delaware. The beaver is surrounded by a string of wampum, which, along with beaver, could be used as currency. SIGILLUM NOVI BELGII translates to "Seal of the New Belgium." Belgium was once part of the Netherlands, and 30 French Walloon families (future Belgians) were the first large group delivered to settle the land and work for the Dutch West India Company.
The Municipal Building, 1914, focuses on the main elements. Actually, as Pine notes, not the seal but "the arms of New Netherland, New Amsterdam and New York are repeated many times on the new Municipal Building." (Pine, p. 22)
Surrogate's Court does another accurate reproduction...
...while the Municipal Building streamlines it, presenting only the saltire arms.
1669. When the English took over in 1664 the seal underwent a radical revamp. King Charles II gave New York (and other lands) to his brother James, then Duke of York, who issued two seals: one for the Province and one for the City of New York. This is the provincial seal; the city seal is apparently lost to history.
The Province of New York extended over "all the land from the west side of the Connectecutte River to the East side of De la Ware Bay.'" (Pine, p. 8) The coat-of-arms in the center belongs to the House of Stuart, and the small crown (a coronet) is emblematic of James, then a Duke. The inner circle, HONI SOIT QUI MAL Y PENSE, translates as "Evil to him who thinks evil." The outer ring, SIGILL PROVINCE NOVI EBORAC says "seal of the Province of New York."
Perhaps because this was the provincial, and not the lost city seal, Surrogate's Court skips this seal, ...
...though the Municipal Building pays tribute to the House of Stuart.
1686. The Dongan Charter of 1686 re-affirmed, in more substantive form, the municipal rights granted to the city earlier in 1664, when the English took over. (But, and this will be important later, the 1664 city government was simply a continuation of the municipal government granted to the city under Dutch rule back in 1654!). With the Dongan Charter, though, city officials were allowed to create their own seal. And there's an interesting anachronism here. The coronet should have been changed to a crown when James ascended the throne in 1685. This seal has the Dongan Charter year of 1686, but is emblazoned with a coronet, a year after James ascended the throne in 1685.

This virtually identical seal is correct in both date and royal head gear, for in 1686 James was King. In fact the only difference appears to be the crown…
Another point of interest is that while it's often reported that the cross-staff was introduced in 1915, it can be clearly seen in the sailor's right hand in both of these early seals. It was actually re-introduced later.

1784. After the Revolution the Common Council ordered a single change to the seal: an eagle on top of a "semi-globe" rising toward the sailor was to replace the royal crown. The year "1686" remained (maybe the Dongan Charter was more attractive than the Articles of Confederation?). Here is where the cross-staff was lost. In addition to the eagle, though, the shield's shape has changed (notice the Surrogate’s Court image above does have the older shield shape), and now there's a lot of foliage sprouting around the top.
The last major change came in 1915 (after many buildings, including Surrogate’s, had been built and adorned with the city seal). Why that year? To celebrate the 250th anniversary of the City's municipal government when a mayor, aldermen and sheriff retained a semblance of power under the English crown. Thing was, the English had adopted New Amsterdam's municipal government of 1654 whole sale, basically giving the Schout, Burgomaster and Schepen English names. (With this in mind, in 1977, the City Council would make one slight change, and 1664 would become 1625, not for the year of New Amsterdam’s municipal government, but the year the Dutch first settled Manhattan, or so they thought--does it ever end?). Anyway, 1915…
Here are some versions of the (pre-1977) seal on buildings throughout the city...
This is the Landmark Preservation Commission's plaque on the Bowling Green fence.
The Louis Lefkowitz State Office Building, 80 Centre Street, 1930. The year 1664 is there, just very tiny.
99 Jane Street again. Because it was installed after 1977, the date should read 1625. Still, beautiful piece of work.
There are great examples of builders and sculptors taking liberties with the seal prior to 1915. In John Buckley Pine's account of the seal's history, he goes off on an entertaining riff about the vagaries the seal was subjected to. I considered inserting [Native American] for "Indian," but since it's already been noted...
In woodcuts of the beaver these animals sometimes appear like dogs and sometimes like pigs with pointed snouts. The Indian is represented with a western war-bonnet on his head, or baldheaded....He shifts uneasily from the sinister side to the dexter side, and when he gets tired he sits down. The dexter supporter is equally unreliable in his conduct and more uncertain as to nationality and occupation.... He exchanges places with the Indian from time to time, strikes different aesthetic attitudes and keeps the Indian company in sitting down occasionally. He also keeps progress with the times in nautical science. He discards the old cross-staff [remember the cross-staff had vanished and so was not available to sculptors or builders!] and contents himself for a while with the lead-line....The eagle, too, is restless on his perch, as perhaps is to be expected of a liberty loving eagle. In 1784 he is rising to the dexter, as required by law, but in the 19th century he mounts in the other direction. Generally he looks where he is going, but occasionally he looks backward to see if he is being followed, as has been his habit of late years. Just after the Revolution, some flowers sprang up around the eagle, but with the increasing population of the City the opportunities for gardening have grown less and the flowers have disappeared, together with the old date 1686 which was retained for a while in the same seal.
226 West Broadway, formerly the Fire Department's High Pressure Services headquarter, 1918. Built during an apparent period of seal chaos, the sailor and Native American lean on the shield with a left facing eagle. Though the sailor's forearm is missing, you can see a plummet neatly wrapped in his floating fist.
But what are you going to say when the police department does this…
Here is the single post-1977 public display I could find of the official seal, with the official year of 1625. It is on the Emigrant Savings Bank...

...the date's wrong.
Added 2/16/11
Two more examples of the seal around town...
This one is from the City Water Department at 179th And Amsterdam...a pretty sad seal. Not so ironically, it looks to have a lot of water stains.
But here's a gorgeous example..and the one other seal in public that has the year "1625." It's on 33rd Precinct at 170th and Amsterdam.
(added 3/6/2011)
Not a seal per se, but a sculpture that certainly picks up the theme--and was quite liberal with it, at 58 Bowery (1924, Clarence Brazer). Originally Citizen's Savings Bank, it's the HSBC at Canal and the Bowery, across from the entrance of the Manhattan Bridge. These guys are really taking a break--most significantly, they've swapped positions!