By Josh Moore and Cecilia Ehrlichman
Over the last several weeks, our archaeology class has been working in the Carleton Arboretum (mostly in a small quarry area, as well as on the Millpond Dike) to learn more about the site’s history. Through a combination of survey and excavation, our class has found and collected several hundred artifacts, indicating that the quarry was used from the 60s to mid-70s, at a period when regulation and maintenance of the Arb was at a historic low. However, without finding an isolated site in the Arboretum or visiting the Archaeology Lab in Anderson Hall, it won’t be easy for interested parties in the future to see what we’ve discovered. That’s where photogrammetry comes in.
To put it very briefly, photogrammetry is the technique of recording three-dimensional information about physical objects through photography. This involves taking pictures from many different angles, and then using software that can create models of objects and sites. If you want to learn more about photogrammetry, you can read about it here. Alternatively, you can click these links if you want to see the photogrammetry projects from past years of this class at the Pine Hill Village or the Women’s League Cabin.
For our final project, we captured the trenches excavated over the course of this term, as well as a number of the artifacts we found through excavation and survey. Take a look!
If you click the play button on Figure 1, you should be able to move around it with your mouse buttons. As you can see from the model, the trench is very shallow, because we reached bedrock quickly. As this was a quarry site, it makes sense that the bedrock would be closer to the surface. On top, there is a crumbly rock which was good for quarrying, which contrasts to the solid bedrock that is more challenging to remove. The way the roots are close to the surface indicates that the bedrock is just below the surface which implies that this ground was artificially formed. Another detail of interest is the formation of the cracks in the stone. This was likely caused by the roots of the severed tree which is evident in the model. Furthermore, you can see how we avoided the roots which cross over the surface of the trench while excavating. The trench, in total, is 1 meter long and 2 meters wide.
Excavation Trench Two is another trench that was dug at the quarry site. Similar to the Excavation trench one, we hit bedrock extremely quickly. In this model, you can see the raised mossy stones and the areas where the trench extends further downward. The feature in the middle where the stone is raised served as a hearth, and on the sides, there is bedrock just below the surface. The location of this trench was chosen because it was the center point for the concentration of materials collected in the survey units. This trench, again, is 1 meter by 2 meters.
Learn more about the trench excavations here.
We dug into the Millpond Dike perpendicular to the ground level, but on the slope of the dike. The model captures the slanted side and the trench. In this trench, observe the stratigraphy on the back interior side. Right beneath the plant life at the top of the trench, there is a layer of dark rich soil. Then underneath, we can see a lighter orange soil, with a sandier composition. The final soil layer underneath this, is an even darker soil. We believe that these different soil layers are a result of multiple trips to bring material and construct the dike. We are uncertain if these took place at close points in time or if they track repairs to the dike. Figure 3 was shot when the trench was about 2 meters deep. Figure 4, shot a few days later, was even deeper (making it the deepest pit that Alex had personally helped to dig).
Learn more about the Millpond Dike excavation here.
This object captures the side of the wall that we believe was once used as a quarry. From cleaning this area and removing some of the soil and debris, we noticed that the floor is bedrock, while the wall is made of a softer, more crumbly type of stone. From the photogrammetry image, you can see the sharp incline of the cliff face, implying that this was likely the result of human intervention in the landscape. The height of the rock wall was about 3 meters, as was the distance from the back corner of the wall to the end of the flat ground stone.
Learn more about the quarry wall here.
The Quarry Site in the Arboretum at Carleton College has served a variety of purposes including quarrying for loose stone and social activities. It seems that the site was in use from around 1966-67 as well as in the late 1980s. The nature of the events is evident from the type of artifacts they left behind. These events included the consumption of alcohol and other carbonated beverages and perhaps food as well. With its secluded spot deep in the Arboretum, this location would have been a nice place for students to socialize.
Learn more about the timeline of social activity at this site here.
This king-sized can of Hamm’s beer was produced somewhere between 1963 and 1970. As a can of cheap beer, its presence supports the hypothesis that this place was used for (likely illicit) social gatherings involving alcohol.
This can was in production around 1974, although the specific model of pull top was in use anywhere from 1965 to 1975. Despite being subtitled “velvet glove”, the red coloring of the glove on the can has worn off.
This can can be dated to the 1960s. Interestingly, while it appears silver now, we theorized that it had been red, but that the red paint had worn off, just like the hand on the Hubein can above. While many of the beverage containers found at the site contained alcohol, this can contained soda. This could indicate that people at these events were mixing soda with alcohol, or that some of them preferred to not consume alcohol or consume soda in addition to alcohol.
This artifact, which is a 5 lb Rath’s Ham Can, is a metal container that was used to store pre-cooked ham. It can be dated to between 1965 and 1974, giving us information on the time period when this site was in use as a party location. The object was extremely rusty, so it is challenging to make out the text on the front, but you can see most of the word “Rath” and other terms including “Gelatin Added” and “Hickory.” On the right side of the model, you can make out text describing a dinner that could be served with the Ham. This includes “Potatoes au Gratin” and “Green Beans with Mustard Butter.” This container indicates that the nature of the activities at this location were not merely events with alcohol, but also included food.
By preserving these places and objects as models, we hope that they may become useful for someone in the future interested in the history of the Arb. The pursuit of historical knowledge, after all, is what archaeology is all about!