Birchbark canoes and Carbon-14 dating

Benson Gray

Canoe History Enthusiast
Staff member
Rob Stevens and I have been trading some emails recently about the canoe described at which the Pejepscot Historical Society had restored and carbon dated in 2017. There are several bark canoes which have been described as the oldest. A few others include the Enys canoe at the Canadian Canoe Museum (, the one at the Peabody Essex museum (, one at the Penobscot Nation Museum, and more. We pondered the idea of organizing a project to get them all carbon dated and see which one really was the oldest. Steve Cayard ( restored the Pejebscot canoe so I contacted him to see what he thought. He kindly responded with a comprehensive explanation of the topic so I got his permission to share it here since others may also be interested in this information. The short summary is that Carbon-14 dating really isn’t accurate enough to reasonably compare canoes from the 1700s. All of the comments below are his with a few minor edits and additions from me. Fun stuff,


The radiocarbon testing for the Pejepscot canoe came from Beta Analytic in Florida, who have done a lot of these. The results can be difficult to interpret, especially for artifacts dating in hundreds rather than thousands of years. A range of plus or minus 30 years is often given, but it's actually more complicated than that. The reason is that the amount of Carbon-14 in the atmosphere has varied over the course of history, so although the rate of decay is well known (the half-life is 5,730 years), the starting point is not the same from year to year. I think sunspots play a role. Archaeologists have developed what they call a "calibration curve" to document radiocarbon levels over time, by testing objects of ages known by other means. This curve ends at 1950, after which nuclear weapons testing made Carbon-14 testing useless. The calibration curve is a wavy line that is then aligned with the tested radiocarbon level of an object, and where the straight line of the test result intersects with the wavy line of the calibration curve, there are a series of hits. The number of hits in any period of time gives a certain probability. Outliers can be eliminated by historical context.

The "conventional" carbon date (before calibration) of the Pejepscot canoe was given as 160 years BP, that is before 1950. This doesn't necessarily mean 1790 literally, with calibration taken into account. There are three hits of the calibration curve in the mid-1700s, one around 1810, plus two outliers. So there is a fairly high probability of an 18th century date, and it seems to favor the mid- 18th century.

The sample tested is destroyed in the process, but it can be quite small, about half a gram or less. The Pejepscot canoe has one end broken off. (Incidentally, the other end was radically modified from the original form, in a crude repair, rendering this canoe essentially a large fragment. It originally had long, pointed ends in the old Wabanaki style.) The broken end had some jagged edges of bark, so that was the logical place to take a sample. The innermost layer of bark growth, which forms the outer surface of the canoe, was taken as being representative of the latest grown material in the canoe. I think that the piece was roughly one inch square and 1/32" thick. The cost of the test was about $600.

Conducting Carbon-14 tests on other old birchbark canoes would definitely be interesting; however it may not provide the final word, due to the considerable range of uncertainty of the results. The construction methods used in a canoe can be a better indicator, if not of the date it was built, at least of the cultural context. There would seem to be a "baseline" model that was in widespread use among many Wabanaki builders, from pre-contact times through the early 19th century. Around that time innovations began to be introduced, a process that continued throughout that century. These varied substantially, even within a given tribe, at a given time. The reason for this variation is largely builder preference, as well as access to new technology, i.e. nails, etc. Joe Polis, for example, was quoted at length by Eckstorm (in Old John Neptune and Other Maine Indian Shamans), discussing his preference for the continued use of wooden pegs and spruce roots over nails and rattan, both of which were coming into widespread use at that time, in the mid-1800s. Also, the 1825 Maliseet canoe (probably built in Kingsclear, New Brunswick) that was brought back to Canada from Ireland in 2007 was built with nails, long before Maine canoes were. I believe there was a strong inclination to adhere to tradition generally, while at the same time, a willingness to innovate radically, as evidenced by such groundbreakers as Joe Ranco.

One very interesting feature of the Pejepscot canoe is the way the thwarts were mortised into the gunwales. Rather than chiseling out a mortise, or cutting a dado on top, the inwales were split open, and the thwart tenons then inserted and pegged. The splits would be done by first soaking the inwales, then wrapping them on either side with cedar bark or leatherwood bark to prevent the split from running, then simply driving a knife into the center of the inwale. The spruce root lashings would also reinforce this structure. The advantages are clear for a context prior to the availability of modern steel tools, both for the simplicity of execution, and for the strength of the joint, since the full strength of the inwale is maintained, without any cuts across the grain. I believe this method would likely represent a very old technique, probably carried over from pre-contact times.

As I said, the Pejepscot canoe is by no means complete; however, there is another Wabanaki canoe that also features split mortises, and it is in much better shape. It is a Penobscot canoe dated from 1810, which was stored in Pemaquid from then until the 1930s, when it was bought by the artist N. C. Wyeth, and brought to his studio in Chadds Ford, Pennsylvania. It is essentially complete, and it features striking long-pointed stems, and is beautifully made, with pegged and lashed gunwales. The video below shows it at the Brandywine Museum of Art.

You also mentioned the Enys canoe, which is in worse shape than the Pejepscot canoe, although its ends appear to be in their original form, even though they were covered with canvas at some point. It is clearly a Wabanaki canoe. Interestingly, this canoe has chiseled mortises, perhaps representing an early adoption of this new technology. The canoe most likely dates from the Revolutionary War period. This time frame can be deduced by John Enys' career in North America, as recorded in his journal. (The journal itself does not mention the canoe, although it is mentioned in a footnote in my 1976 edition; the family history only offers that the canoe came from Canada). Enys arrived in Quebec in April 1776 with the British Army's reinforcements to break the siege laid by the Continental Army under Benedict Arnold. Enys' subsequent travels during the war carried him to Trois Rivieres, Montreal, Lake Champlain, and Saratoga. He went back home to Cornwall on leave in 1782, returning to Canada in 1784, when he served for 3 years in Montreal and Ontario. Before leaving North America for the last time in 1788, he took a tour of the new American nation, from New England to Virginia.

Enys was in the Wabanaki region primarily during the early war years. There were Maliseets present on the St. Lawrence in the 18th century, particularly in the area of Levis, Quebec, which is directly across from Quebec City. Another possible source of the canoe was the Arnold expedition from Maine to Quebec in the fall of 1775, which included a number of Penobscots with their canoes. It is possible that some of these canoes were left in Quebec in the ensuing battle that winter. So it would seem that Enys' best opportunity to acquire the canoe would have been in Quebec in 1776. He might then have sent it on a ship with a friend, or brought it with him to Cornwall in 1782, when he sailed from Quebec. In 1788 he sailed home from Virginia.

The Penobscot canoe at the Peabody Essex Museum (PEM) has been in collection since 1826 at the East India Marine Society. Built with chiseled mortises, this canoe has the fully pegged and lashed gunwales of the early method of construction, one of only five Wabanaki canoes in existence built this way, that I know of. Of these five, the PEM canoe, the Pejepscot canoe, the Wyeth canoe, and the Enys canoe have wide gunwale lashing groups, relative to the spaces for the ribs. The fifth canoe, at the Penobscot Nation Museum, has pegged gunwales (pairs of blind pegs, rather than through pegs like the others), but it has narrow lashing groups, a later style which places it in the mid-19th century. Because of its early date, the 1825 Maliseet canoe that was in Ireland should be included in this group; it also has wide lashings, even though nails were used in place of pegs. It was repatriated to the Maliseet people, who call it the "Grandfather Canoe" in 2009, and is currently housed at the Beaverbrook Gallery in Fredericton, New Brunswick as described at in more detail.
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