Let mee now describe this military fortresse which naturall reason & experience hath taught them to erect, without mathematicall skill, or use of yron toole. They choose a piece of ground dry and of best advantage, forty or fifty foote square. (But this was at least 2 acres of ground.) here they pitch close together, as they can young trees and halfe trees, as thicke as a mans thigh, or the calfe of his legge. Ten or twelve foote high they are above the ground, and within rammed three foote deepe, with undermining, the earth being cast up for their better shelter against the enemies dischargements. Betwixt these pallisadoes are divers loope-holes, through which they let flie their winged messengers. The doore for the most part is entred side-waies, which they stop with boughes or bushes as need requireth. The space within is full of Wigwams, wherein their wives and children live with them. [...] This Fort was so crowded with these numerous dwellings, that the English wanted foote-roome to graple with their adversaries, and therefore set fire on all.

-Philip Vincent, A true relation of the late battell fought in New England, between the English, and the salvages vvith the present state of things there. 1637

This is a description we have of Fort Mystic prior to the 1637 massacre, where English settlers killed somewhere between 400-700 Pequots.

Military technologies were no exception to the type of hybridization that took place on peoples, practices, and tools in early colonial North America. The enduring myth of American Indians as impotent in the face of European technology is unfortunate, especially as it is contrary to decades of scholarship. Tools and technology were an interface between English and Indians, not a one way street; each population group built upon the practices of the other. This is most often acknowledged in the realm of agriculture, hunting, and fishing, especially in Virginia where Powhatan Indians fed the Jamestown colonists for decades. Early English forts in North America were not dissimilar from Vincent’s description above. Jamestown was constructed of upright logs, as was the second fort on Castle Island (where Fort Independence is). In Subject Matter, Joyce Chaplin points out that “Settlers might claim the technological achievements of their mother country, but they had not yet replicated all of them in America, where they lived more like Indians than they wanted to admit.”

Nonetheless, Indians were eager to adopt many of the tools and technologies that Europeans brought with them. There were numerous opportunities for them to procure not only trade goods, but also to learn craft skills that supplemented those they already had. With the exception of a royal proclamation in 1630 outlawing English settlers from teaching Indians to repair or make firearms or any of their components, there were no prohibitions on teaching English trade skills, such as masonry or carpentry. In addition to filling an English labor shortage among the earliest New England settlers, imparting European trades onto the American population played into English desires to Christianize and civilize the indigenous population. Some of the places in which it was common for Indians to learn European craft were the praying towns of the Massachussets Bay Colony, established by John Eliot in the 1650s. The English did not want Indians using their technology without first being absorbed into English culture, as such an act would represent a subversion of English control. In fact, John Eliot stressed that before they were even baptized Indians must live under English government. The first of these praying towns was Natick. Here Indians constructed houses, an 80 foot bridge over the Charles River, and a meeting house that especially impressed the English. They also planted orchards and fenced in land for growing crops. All of this was done in the English manner and under the watchful eye of English missionaries, who remarked on the Indians’ ability to quickly and correctly erect many of these structures.

At Natick and the other praying towns, they also built forts. English settlers often assisted in the construction of native forts, such as the one on the Thames River in Connecticut which Mohegans defended against a Narragansett attack in 1645. English laborers also constructed a fort for a Narragansett sachem (Pomham) sometime in the 1640s. The Great Swamp fort you describe was not yet complete at the time of the English attack in 1675, but there is little doubt it was heavily influenced by European construction techniques; rudimentary blockhouses and flankers were found at the corners, features not normally seen on indigenous forts. Most likely to have served as foreman on this fort was a Narragansett Indian by the name of Stonewall John (sometimes Wallmaker John). His name derived from masonry skills he learned while living with the English.

The start of King Philip’s War in 1675 soured relations between English settlers and the Christian Indians among them so much that many Indians returned to their communities. Stonewall John was likely among them and had no shortage of motivation to use his English-acquired skills in defense against the English. In March 1676, Roger Williams met with party of Narragansetts who had burned down his plantation and asked them why they had done it when he had taken them in as neighbors for the past decade. It was Stonewall John who responded: “You have driven us out of our own Countrie and then pursued us to our Great Miserie, and Your own, and we are Forced to live upon you.”

Much like the massacre at Fort Mystic, the Great Swamp fight resulted in hundreds of Indian deaths and the destruction of the wooden fort. Many of the surviving Indians retreated to the Queen’s Fort. This one, also a likely product of Stonewall John’s knowledge, was constructed of stone, this time to include a semicircular bastion and flanker in keeping with 17th century European military engineering, the likes of which could be found in manuals such as Robert Ward’s Animadversions of Warre. The Queen’s Fort was located at the top of a hill and incorporated the natural boulders there, but also displayed European-style masonry. Some at the time found it impossible to accept that Stonewall John was an Indian due to the works he is credited with. In fact, well into the 19th century, historians have been skeptical. James N. Arnold credited the forts’ construction to Joshua Tift (or Teftt), an Englishman who had been accused of fighting on behalf of Indians, but gives no sources.

As far as continued use of forts, I wish I could say more, but I’d be speculating. However, during King Philip’s War, only the Narragansetts at the Great Swamp tried to withhold a besieging force and they failed. I don't know of further examples, but that is certainly not to say there aren't any.

Further reading :

Jill Lepore, The name of war: King Philip's War and the Origins of American Identity

Joyce Chaplin, Subject Matter; Technology, the Body, and Science on the Anglo-American Frontier, 1500-1676

Patrick Malone, “Changing Military Technology Among the Indians of Southern New England, 1600-1677”

Native American people had a long history of constructing fortifications that predates European influence and continued after contact. That said, Europeans did have some clear influences on Native American fortification design. To say that the Narragansett fort was built in European style might be misleading. While there are some European influences, the majority of the construction followed from a long tradition of Native American fortification construction.

When most people think about Native American towns and cities, they likely think of open villages with huts or long houses set among the woods. While may have been common a very, very long time ago, by 1675 most Native Americans in the north east lived at least half the year within well constructed walled towns. Most scholars think the shift from open villages to fortifications in Native American nations began around the year 900, likely around the same time when Cahokia's walls were first constructed. Some unknown cultural shift caused Native American people to prefer compact walled towns at the top of hills as a defense against the increase in warfare among Eastern Woodland peoples. Most of these town fortifications were round wooden palisades, some double-walled at vulnerable positions, and most with platforms to allow people to fire bows from protected elevated positions. By the 1300s, some cities were constructing particularly impressive fortifications, with multiple layers of double-thick wooden palisades of increasing heights as they moved inward. The individual logs used could be up to 6" thick, and stand as tall as 35' on the interior keep.

In 1535, Jacques Carter described one of these towns. (Any parenthetical sections are my own notations and are not original.)

The village is circular and is completely enclosed by a wooden palisade in three tiers like a pyramid. The top one is built crosswise, the middle one perpendicular, and the lowest one of strips of wood placed lengthwise. (He is referring to the way the logs are arranged.) The whole is well joined and lashed after their manner, and is some two lances in height. (20-30 feet) There is only one gate and entrance to this village, and that can be barred up. Over this gate and in many places about the enclosure are species of galleries (rooms or platforms) with ladders for mounting them, which galleries are provided with rocks and stones for the defense and protection of the place.

It sounds pretty similar to a Motte-and-Bailey style castle common in Europe pre-gunpowder. It has tall wooden walls, crenelations, murders hole type arrangements, and an interior keep. Sometimes they utilized natural moats as well. But they were designed contemporaneously and independently. Post-contact, some changes came directly from European influence, as well as in reaction to European contact. In the summer of 1621, Edward Winslow, of Mayflower fame, commented on a fort built by Nemasket people to protect against, ironical enough, the Narragansett people, whom they were currently at war with. It was described as a wooden palisade with two gates constructed at least 20 years prior. It was square, and about 30'-40' per side. Thus we see the main result of European contact: straight walls.

We know that starting in the early 1600s French military advisers had helped Native American people design more robust fortifications by adding towers at the corners and using straight edged walls, among a few other minor suggestions. It is likely this information disseminated itself throughout the fortification building world of Native Americans over the years. These bastions could help defend the whole straight wall of a fortification by allowing for sweeping fire in two directions with arrow and gunfire; sometimes even cannons.

As to the fort constructed around 1675 by the Narragansett people, we have at least one contemporary description. An English scout, Joseph Dudley, wrote of it in his report

...within the cedar swamp we found some hundreds of wigwams, forted in with a breastwork and flankered (a projection in the fortification, probably corner towers), and many small blockhouses up and down, round about.

Again, this sounds similar to European forts, and likely looked similar to the fortifications at Jamestown in 1675, or to Fort Detroit, built a few years later. Yet it also sounds very similar to other earlier Native American forts which had dotted the landscape for centuries. Usually when a northern Native American group settled in for the winter they built some kind of fortification. Larger groups built larger and more complex defenses. Therefore, while European influence should be acknowledged, the Narragansett fortification designers were mostly influenced by a long tradition of Native American people building fortified towns in a similar style with a few European innovations. Outside the rare masonry fortifications like Castillo de San Marcos, there really wasn't a lot of difference between European and Native American fortifications in the late 17th century Americas.

Unfortunately for the Narragansett people, the fortifications in the swamp were incomplete when attacked in 1675, which contributed to it's fall. Yet even in its incomplete state it was difficult to assault. The massive casualties among the Narragansett people came almost exclusively from the burning of the village within the fortifications once the defenders were driven off the walls. Most of the warriors escaped. All wooden fortifications were vulnerable to fire, and a long standing tradition to keep the bark on the wood rather than strip it off as European fortification designers might contributed to their vulnerability.

After 1675 various Native American people continued to construct fortifications, as they always had, though they were rarely as impressive as they had been. In 1738, French explorer Pierre Gautier de Varennes de la Verendyre visited a Mandan town in the Missouri River valley.

I gave orders to count the cabins and we found that there were about one hundred and thirty. All the streets, squares and cabins were uniform in appearance; often our Frenchmen would lose their way in going about. They kept the streets and open places very clean; the ramparts are smooth and wide; the palisade is supported on cross pieces mortised into posts fifteen feet apart with a lining... As to the bastions, there are four of them at each curtain wall flanked. The fort is built on an elevation in mid-prarie with a ditch over fifteen feet deep and thirteen to eighteen feet wide. Their fort can only be gained by steps or posts which can be removed when threatened by an enemy.

The Mandan town constructed many fortified towns like this throughout the Missouri River Valley.The Arikara people in what is today the Dakotas built fortifications as well. In 1795, Jean Baptiste Trudeau described their fortified towns as tall mounds of earth with five foot wooden palisades at the top. As Native American power waned, so did their ability to construct fortifications which could do much other than prevent other weakened Native American nations from attacking them. They would do little to stop American, French, or English interlopers.

Sources: Primarily Craig S. Keener's An Ethnohistorical Analysis of Iroquois Assault Tactics Used against Fortified Settlements of the Northeast in the Seventeenth Century which contains many more vivid descriptions of Native American fortifications, as well as in depth analysis of Iroquois siege warfare.

Also useful is David E. Jones's Native North American Armor, Shields, and Fortifications

As a follow up question, if indeed there were other examples of native tribes building fortifications, and specifically European style ones, did they become more common as more colonists arrived and Europeans became more influential in the area?