Way Back Wednesday: Marine Life

A few members of our team went into the archive annex this morning to do some housekeeping: checking on and changing silica gel packets in the boxes of small finds. We have indicator strips that show when a box is no longer dry due to ambient humidity. Lauren grabbed a random box of environmental archaeology small finds to have a nose around, and, much to her surprise, it was mostly material she herself had found and recorded while managing environmental processing in 2013: stycas, glass and ceramic beads, and some flint flakes. In an amongst those bits from nearly a decade ago, two examples of local marine life appeared.

First, another St. Cuthbert bead! This one was found in 2010 in a burnt context from Trench 3. It seems to be associated with the stables phase of the trench, around 10th century. We hope to do a deep-dive post (pun intended) on crinoids in the future, as they have been on our mind after the large one we found earlier this season.

The second was something that struck Lauren and the finds team as odd years ago: it looked like a tiny cowrie shell. True cowrie shells (family Cypraeidae) were often found historically in Indian Ocean trade networks, so this miniature version was separated out as a small find because it seemed non-native to the area. The sample was taken in Trench 1, associated with an early medieval linear feature. Further research shortly after the dig in 2013, however, revealed more information about this tiny mollusc.

This shell is from the family Triviidae which has a two species local to the North Atlantic and North Sea, but the species are often called the “European cowrie” and “northern cowrie.”

The European or spotted cowrie is used to refer to trivia monacha (da Costa 1778), a carnivorous snail that lives at the low tide of the shore. They usually have dark spots on the pinkish upper shell, which our specimen does not have.

The “northern cowrie” is trivia arctica (Pulteney, 1799) which has an unspotted shell. These species were actually thought to be one and the same until 1925. Both species prey on sea squirts, and they are in turn food for fish like Atlantic cod, who also occasionally turn up in our animal bone. Our shell is also a bit chalky to the touch, but it’s not immediately clear if ours is a proper fossil and thus old at the time it was deposited in the sample or if it was alive contemporary to the occupation of the context from which the sample came.

Living t. arctica specimen, image by Frans Slieker (NHMR).

Why do we care so much about tiny molluscs? Why does it matter that this was found here? Molluscs are extremely useful when studying the environment in the past. Some snails have very specific habitable ranges that can help us infer climate information, and today is especially valuable in understanding periods of climate stability and instability in the past. Others are fantastic to chemically profile to understand the water and plant life signatures for a particular region, which was a methodology we used in our interpretation of the Bowl Hole burial ground skeletal material.

This particular shell was saved because it looked different from the mollusc shells we had been finding previously. It turns out it was local, but it was probably not being collected for food unlike the winkles we find en masse, so we don’t have examples of it in the record.

For more information and more images:

Gallery of the Family Triviidae via National History Museum Rotterdam

Differentiating the species

T. monacha, European cowrie: entry for Encyclopedia of Life, entry in World Register of Marine Species

T. arctica, Northern cowrie: entry for Encyclopedia of Life, entry in World Register of Marine Species

Labels, Labels, Labels

We always tell students and visitors that archaeology has way more paperwork involved in it than you see in popular culture portrayals. In addition to myriad paper forms and their increasingly digital counterparts, we also rely heavily on labels and labelling conventions that are used in every department on site.

Tools of the trade.

Our trusty Sharpie is always on hand for label emergencies. (Sharpies are also like currency on a dig, you protect them and hand them over only occasionally and with great suspicion of those you loan it to.) What may seem like normal paper beside it, however, is a little bit of high-tech stationary: it’s known colloquially as Tyvek, which is technically a trademark in the United States, but has become a generic name for the type of material our labels are made from. This phenomenon is known as “generification,” where a brand becomes a generic term, thus putting the brand’s legal right to their name in jeopardy. For example, plasters in the UK are called “band-aids” in the US, named for the brand “Band-Aid.” It happens sometimes with the word Sharpie in place of other permanent markers too! Even words like elevator and zipper were once trademarked, but they became the word everybody used for those inventions.

Tyvek is a synthetic material made of high-density polyethylene fibres spun together and trademarked by Dupont. HDPE used in things like plastic bottles, and they can be recycled: they are labelled as number 2 with the little recycling logo to ensure they are processed in the proper recycling stream. Tyvek is commonly seen as house wrap on construction or renovation projects, but it can be used for things like PPE (personal protective equipment) and packaging as well. The way the fibres are smushed together and not woven makes the material water-repellent, and thus weatherproof. It also means you can’t rip the material with your bare hands; you need sharp scissors or a utility knife. They can be written or printed on, but, as you can imagine, with the amount of labels we are writing every day, it makes more sense to just use a Sharpie.

We use these labels in finds trays at the trenchside and as-yet-unwashed at the washing station, in the blue plastic drying trays for washed bulk material and wet environmental samples, on the sorting trays of bulk material, and in the environmental samples themselves.

Environmental samples that have been floated drying in blue trays.

The finds trays at the trenchside have two bits of information on them: the site code and the context number. The site code includes the letters BC for Bamburgh Castle and the last two digits of the year the material was excavated; everything we find this year is labelled BC22. Our context number is written in a circle or in parentheses to represent an area of activity or occupation within the trench. This same information is copied onto new labels when the material is being washed to denote where the drying material has come from and when it was found. When the material is dry and ready to be sorted, the label is kept on the sorting table or tray and copied onto bulk finds bags (more on that in a mo).

Bits of animal bone excavated in 2019 in the middle of sorting.

Environmental samples also have that same information, but with an added number written in a diamond denoting what sample it is. When we take a sample of a context, we assigned the sample a number. We put multiple labels in each bucket or bag of sample, as well as labelling the bucket or bag directly. When we separate the heavy material from the flot (which is collected in a little mesh bag), each of those are labelled too! The sheer quantity of labels is unending! In the picture below, you can see an old sample that was in storage was also marked with how many total buckets of sample were taken, here “2 of 3.”

An environmental sample that has not been floated yet.

When we are dealing with bulk finds that have dried and are being sorted, we write the site code, context number, brief identification, number of pieces, and weight in grams. It goes on a little label AND on the plastic bag.

Sorted animal bone.

For small finds, which are the more unique or unusual artefacts we find, we do the same process for labelling a bulk find with one more added number: a small finds number. These numbers are taken out consecutively from a register during the season and written in a triangle. Here’s the bone toggle with all the information required to track and analyse it.

A small find and its bag.

Is that too many numbers and letters for you on a Sunday evening? I understand. To settle down, have a bowl of soup.

Week 2 Round-Up

This week we have had the students rotating through even more jobs than last week! In addition to finds washing and sorting and digging crews, we designated teams to work on environmental processing and the massive finds database we are building.

Environmental processing is explained further here, but it is a method of recovering extremely small organic material like charred seeds by agitating soil gently while water flows through it.

The most talked-about find in the environmental sample was a large crinoid! Crinoids are sea lilies (related to starfish and urchins), which first appeared on earth 300 million years BEFORE the dinosaurs. There are still extant species today! During the medieval period, the bits of their stem column worked as natural beads, because often they are found with a round or star-shaped hole in the centre. Locally, they are known as “Saint Cuthbert’s beads.” If we find any more, we will for sure do an in-depth post on them!

Crinoid fossil.

In the castle’s labyrinthine lower levels, we worked on updating and reconciling data in our finds archives and confirming shelf-marks. Boxes of interesting finds were opened, reassessed, passed around, and discussed while doing this archival work. We even found material that was discovered, recorded, and bagged by Constance and Lauren back when they were new staff in 2013!

During finds washing and sorting of early medieval contexts, several pieces of worked bone were discovered, including what looks like a toggle. We also had an strange tooth that was possibly worked which at first looked like bear, but it may actually have belonged to a seal. Wild bear (as opposed to imported bear) extinction is hard to date, as no one agrees what part of the medieval period they disappear, but seals are still present around the Farne Islands visible from the castle.

In the trenches, digging slowed down aside from the removal of the rubble in the two chambers split by the masonry-and-brick stacked walls. The arch has been further revealed!

Revealing the arch.

We have also begun to shore up walls and ground surfaces to prepare for the removal of the massive bits of rubble. Hard hats are now required in the rubble areas.

The trench team started recording the masonry via photograph and then via plan. Photographs are taken on a digital DSLR camera in colour, and each is recorded in a catalogue. We use large poles as scales to represent up to two metres!

Photographing each wall face.

Planning involves drawing the features and contexts in the trench to scale. What’s great about planning is that you don’t need to be a great artist to do it; when you use a planning frame like pictured below, you simply have to copy each square of the frame into a set of boxes on the grid paper. It’s like in colouring books, where you have to move a picture from the left-hand page into empty boxes on the right-hand page.

All smiles when planning.

We hope to clear more rubble out next week once everything is recorded thus far!

Soiled! Part 2

Last week, we gave a primer on recording the colours of soil, and this week we are going to talk a little bit about soil types!

One way soils can be classified is by their texture, which is another quality we can experience through our own senses. You don’t need fancy equipment to tell apart different soil types, just the ability to feel and work the soil between your fingers. You could use fancy equipment, to be fair, but who wants to bother with that? What you are actually trying to compare is something called grain size. There are three main types of soil, plus a more nebulous category called loam that combined the three main types with lots of organic matter (humus). From largest grain size to smallest, we’ve got sand, silt, and clay. The proportions of those types in any given soil are what constitute the texture. If you do employ even simple measuring equipment, the US Department of Agriculture has developed a series of maximum diameters of the particles to differentiate the various types; their system has been recommended internationally by the Food and Agriculture Organization, a department of the United Nations. (Other organisations have their own systems, so you may find inconsistencies from site to site as to what counts as what.)

Stock image of three main soil types found on GardenTutor.com

Sand is made of silica grains like bits of quartz you can see easily, and it feels scratchy in your hand even when wet. Silt is smaller and a bit more difficult to see without magnification; it feels smooth like flour when dry, but can be finely gritty. Clay are the smallest grains, not visible to the naked eye, and they easily smear and get stuck in your fingerprints.

A helpful graphic from Madhav University.

You can also describe soils that are composed of more than one particle size range using a two-word compound. The second word is the major component of the soil, while the first word describes what it is mixed with. For example, if you have mostly silt but can feel individual grains easily, you might have sandy silt. For these combined soils, many flowcharts exist to help you determine what you’ve got. The one below is a pretty standard example that uses simple methods of testing without pulling out calipers.

S.J. Thien. 1979. Journal of Agronomic Education. 8:54-55

We record the texture of every context on site when we discover different areas of activity in the trenches. When we run environmental samples, we also record the texture before any soil is placed in the flotation tank. Texture is important because it determines how water can move or be retained in the soil, which in turn affects how plants and animals can use the soil. It also affects how much air moves through the soil and what nutrients may be present.

Soiled! (Part 1)

We are hoping to start up our environmental processing next week when environmental archaeologist Alice joins us again, but until then we wanted to give a refresher on that beautiful, beautiful matrix: the soil. While soil may just be dirt to most people, to archaeologists and soil scientist it’s a massive book to be read right beneath your feet!

There are a number of qualities we can use our senses to experience and describe, but we’ll just discuss some of the most common characteristics we look for and record on data sheets.

The first thing most people notice about soil is the colour! Colour can help be an indicator of the type of soil you’ve got if you’re familiar with the local geology, as it’s mostly based on the mineralogy (for example, yellow may signify clay in one area, but red might signify clay elsewhere because of what minerals are present). Organic matter leads to dark brown and black soils, while iron-rich soils are reds, oranges, and yellows. Soils that have been leached out tend to be light greys and beiges. Soil colour can also be affected temporarily by water retention; think of the difference between dry sand and wet sand. Archaeologists have two main ways of describing and recording soil color: the “three-word method” and the Munsell method.

The former is what we use on site at BRP, and it is pretty easy to use once you know the order of descriptors. The first word is always “light,” “medium,” or “dark.” The third word is always the main colour. The second is a colour word sandwiched in the middle with the suffix “-ish” that describes the main colour. For example, the soil could be described as medium yellowish brown.

Medium yellowish brown soil.
A bit of earth.

Unfortunately, once in a while when looking for a way to describe the soil we had in the old Trench 3, your brain would immediately go to “medium brownish brown” which is completely useless but always hilarious.

The Munsell system is a bit more complicated but meant to be an international standard. Teams purchase (very expensive) little binders with pages that look like paint swatches depicting the spectrum of Earth’s soil colours. Every shade is given an identification code with letters and numbers. They are based on three characteristics: hue (redness), value (light or darkness), chroma (brightness). Hue is organised as a ratio of yellowness to redness.

Munsell page. You can see how the numbers increase down the axis and from left to right.
The code in the top right means 10 parts yellow to 1 part read.

The drawbacks of a Munsell ID however are that it’s harder to picture the soil colour in your mind unless you’ve memorised the whole chart. Sure, you can figure out the colour family by looking at the hue portion of the ID, but it’s not as easy to imagine the exact value and chroma from the associated digits. You can make relative comparisons by knowing the higher numbers, but it’s unlikely you could guess the exact light/dark or bright/dull numbers.

Stay tuned for Part 2 next week!

New Field Work Dates for the Bradford Kaims Project

Three new dates have been set for field work out at our prehistoric wetland. The dates are Wednesday 17th October with follow up sessions on Wednesday 24th and 31st October.

Volunteers coring for soil samples at the site.

We plan to do some survey and return to the excavations of Trench 6, to try to get as much done as we can before the winter sets in. There may also be opportunities for field-walking depending on the availability of harvested fields, and as always there is the chance to do some filming.

Please come along if you can, dressed for weather, and wellies are recommended. As usual, no experience is necessary!

A somewhat better photo of the Bradford Kaims arrowhead with a scale.

If you would like to volunteer please send an email to Graeme Young at graemeyoung@bamburghresearchproject.co.uk or call him on 07711187651.
We very much hope to see you there!
If you are unfamiliar with the project please click here for more information. To look at our most recent video overview of the project please click here. You can also click on the ‘bradford kaims‘ tag to the right of the screen to see all the blog posts relating to the site.

This Week in Photos

Spending more and more time holed up in the windmill, databasing and doing other environmental odd’s and ends, I’ve come to appreciate the re-introduction to the trenches and interesting finds that Friday Trench Tours provide. In order to stay apprised of the going-on’s (and to appease my archaeological cravings), I’ve taken to accosting my fellow supervisors for updates and explanations of new features, intriguing finds, and general archaeological musings, on a semi-regular basis. Since most of you readers don’t have that option, I thought you might appreciate a taste of what Friday (and the preceeding week) offers our volunteers and staff. On that note, I present our first ever “This Week in Photos”:

ENVIRONMENTAL (an oft-neglected aspect of BRP archaeology, and never a part of trench tours)

WE’VE FINISHED TRENCH 7 ENVIRONMENTAL PROCESSING!!!

Some of the specimens in the Trench 7 flotation residue.

This is very exciting for me, since I’ve been working towards this goal since last season. Thanks to all those people who helped me with the endless flotting, sorting, and discarding of the BC08 Chapel Samples.

Lally and Jani sorting the last Trench 7 sample.

We’ve also been working our way through BC12 and BC11 samples in order to free up sample buckets for use in the trenches. The greedy people keep wanting to do important environmental archaeology, filling up my freshly washed sample buckets faster than I can flot them.Alex, Jess, and Trench 1 kindly filled a wheel barrel FULL of sample bags for me this week.

Lauren and Anne flotting a very clay-ey sample.

The flot tank at work.

Flotting of BC12 T3 (400) and (401) and BC12 T1 (206) and (207) all revealed somewhat unusual samples… stones, bone, and shell galore. Looks like cobbled paths and post-hole fill are the trending contexts this week. It will be interesting to see what the sorts reveal.

Flot and environmental samples drying in the sun.

TRENCH 3

Greetings from Steph and Maria, the Trench 3 Assistant Supervisors! Despite the loss of our supervisor and beloved leader this week (Jo, we miss you!), we have tried to plough ahead as usual, and have certainly been rewarded with some interesting developments.

Media (“T”) filming progress in T3.

In the South of the trench, we’ve exposed more of our strange ‘doughnut’ stone and the packing stones around it, as well as excavating and sampling a pit nearby.

1387: “Doughnut stone”

The ‘doughnut’ stone may be a drain associated with the nearby metalworking structure. The relationship of the nearby pit and surrounding shell deposit with the structure is as yet unknown, but they may also be related. Shell is indeed a raw material used in some metalworking processes (e.g. cupullation)

Jessica G. and Victoria planning the SE corner of T3.

Danielle and Harry planning the SW quadrant of the SE corner of T3.

After cleaning, photographing and planning the southern half of the trench, we turned our attention to the north which has received less attention so far this season.

What we have affectionately termed the T3 “Sexy Section”.

Originally believed to be earlier in date, lines in section are now suggesting that this higher end may actually still be later than the south, so we started off with a big clean to expose the contexts hidden by the recent heavy rain!

Cleaning in the NW Corner of T3.

Kelly excavating in the NW corner of T3. The appearance of unusual clay and shell deposits suggest a possible floor.

Considering the few contexts visible in the Northern part of Trench 3 at the end of last season, this week has proved surprisingly fruitful! An interesting burning(?) feature apparently associated with a strange triangular spread of rocks and pebbles has already appeared…

Left-centre – Linear scatter of large pebbles; Bottom right corner – Strange triangular spread of rocks and pebbles.

.as has what appears to be a linear of bluish grey soil containing a pebble scatter.

Contexts were proving particularly hard to distinguish in the NW corner, so we have started digging by quadrant in this area.

Tyler excavating the east quadrant of the NW corner.

This involves splitting the area into four quadrants and digging two of the four down. This will expose 4 sections which will hopefully provide greater clarity and aid us in our interpretation as we excavate this complex area down. 

TRENCH 1:

T1 students trying to look busy.

Over in Trench 1, the main effort has been on finding the return of the timber building and the robbed out stone building. After pulling back the tarp in the old trench to reveal where the walls were heading, we popped two sondages into the area of the trench we have been working in. One sondage was placed in the SE corner, revealing a cut cut by another cut.

Sondage in SE corner of T1, and patches of boulder clay coming through.

The other sondage was placed in a possible pit in the NE area.

Sondage in NE corner of T1.

Judging by what we could see in the old part of the trench, the timber and the stone building both cut the pit. We are still in the process of excavating the pit, so we don’t yet know whether our theory holds. We’ll let you know the results soon!

T1 Supervisor Alex tidying the NE corner for a photograph.

Stay classy bloggers 😉  — Jessica

FINDS

Finds Assistant Supervisor Jeff and Supervisor Kirstie caught on camera in the AsSup’s office.

Finds update to follow later this week…