Oak Island archaeology update : bones and swages

We’ve learned some interesting things in the first few episodes of Curse of Oak Island this season. I’ll go through the most significant, from my perspective as an archaeologist.

Bones

A couple of years ago, the Curse of Oak Island (COOI) team recovered 2 fragments of bone from their drilling in the Money Pit area. These were initially identified as human, with one showing European ancestry, and the other tied to the Middle-East. At the time, we didn’t get much information about the analysis itself.

In the “25 top moments you never saw”, we get some very interesting additional information. In one of the clips, someone from Wyndham Forensic Group in Guelph, Ontario, tells us that they have analyzed DNA samples “already in solution”, and that sample 3 of 9 contains human DNA.

Let’s work out the implications of the very carefully measured language used by the Wyndham rep. That the DNA was already in solution when received at Wyndham means that it was extracted from the bone and purified elsewhere. They received little phials that possibly contained DNA extracted from the bone. Wyndham then analyzed the liquid, probably looking specifically for human DNA. They found human female DNA in one of the nine samples they analyzed.

What she doesn’t tell us is equally interesting. We don’t know whether they looked for other DNA than human. We don’t know what method they used, although the most likely is PCR. That method allows you to find the kind of DNA (human, bear, whale) etc that you are looking for, even if it is in tiny quantities, but it is not good at finding DNA you’re not looking for. If you use a human primer, you will find human DNA if there is any. You won’t necessarily find any other kind of DNA.

In other words, if there was non-human DNA in the samples, we might not know it. The fact that she specifies that one sample contains human DNA strongly points to contamination. Contamination is a huge problem in DNA studies. Ancient DNA labs take all kinds of extreme measures to avoid it, and it is still one of their main problems.

If you are looking for, say, bear DNA from a bone sample, contamination by human DNA is less of a problem. It is unlikely that the sample will be accidentally contaminated by bear DNA, unless someone had bear steak for lunch in that lab that day. But if you have a bone that you know is from a bear, and extract a DNA sample from it, you might very well find human DNA in it also. That normally isn’t a problem, because you’re not interested in the human DNA, only in the bear.

When dealing with an unknown, especially if you are looking for human DNA, the contamination issue becomes extremely significant and problematic. Humans extracted the DNA sample, and therefore, contamination is sometimes difficult to rule out.

At this point, I really don’t have enough information to evaluate the claim that the Money Pit bones are human, but I strongly suspect that the human DNA Wyndham found is from contamination. I would want to rule that out before I accept the claim. The bones could be human, but at this point, there is a high probability that they are not.

A good research project gives details of its methods, assumptions, etc, so that its audience can have the tools to properly evaluate its claims. So far, the COOI team has not done very much of that, and certainly not in the case of this bone analysis.

Swages

In last week’s episode (Core Values), the team recovers two iron objects from the western end of the Island (Lot 21 area). These are initially identified as hammers by metal detectorist Gary Drayton, but later specified as swages (swage hammers?) by guest analyst Carmen Legge. He claims that these are rare finds, that they could date from the 14^th century, and that they suggest intensive drilling and mining operations on the island.

Let’s take those claims one by one. Swages are blacksmith’s tools used to form iron into predetermined shapes. Whether these are simply hammers, or whether they are swage hammers is very uncertain from the pictures shown.

The objects both have clear hafting holes and were probably used as hammers, swage or not. The V-shape at the end of one of the objects, which Legge argues makes it a swage hammer, seems at first sight to be the result of use-wear or breakage, rather than a design feature. It seems to be absent from the other one. Regardless, this is not terribly important.

The claim that swages and swage hammers are rare finds is surprising. They are very durable, large, and heavy, which means they are easily found by archaeologists. They have been used daily in every smith shop for millennia, which means there is a lot of them around. Just for interest, here is PDF of Matthew Carter’s archaeology Masters Thesis from Memorial University on the excavation of a 17^th century blacksmith shop in nearby Newfoundland.

The presence of swages and hammers in an area suggests a blacksmith shop. They certainly don’t by themselves, suggest intensive drilling and mining operations. Nothing inherently ties hammers and swages to drilling and mining, and nothing inherently ties blacksmithing to drilling and mining. That claim is very weak, just on its face.

I would hope that on the basis of the hammer finds, the team (especially Laird), has looked at that area in more detail to see if it is a blacksmith shop. It is difficult to tell from the images shown on television, but, the ground seemed very disturbed where the hammers were recovered. Perhaps that means it was already surveyed and or/excavated?

The claim that the hammers could be from the 14^th century is one of those classic “could it be” moments of pseudoarchaeology. Yes, similar tools were used in the 14^th century, but they were also used in the 18^th century, from which most of the archaeologically visible activity on the island seems to date (not surprisingly). Further analysis of the objects might give them a better date, but for the moment, if we go by context, they are 18^th century or later.