Small Town Archaeology

This weekend, Bret Weber, Eric Burin, and I conducted a little backyard archaeology. Actually, we helped Bret build a “French Drain” between his garage and his alley in Grand Forks, North Dakota. It happens that the garage is lower than the surrounding alleys meaning that water flowed down into his garage during heavy rains.

Our solution to the problem was partly inspired by my work over the past few years at the South Basilica at Polis Chrysochous on Cyprus. This church was built across a natural drainage, on the slope of a hill that runs from the city to the coastal plain. As a result, the church must have constantly endured erosional problems particularly on its south wall which stood perpendicular the the flow of water down the drainage. The presence of a road upslope from the basilica did little to slow the flow of water to the south wall of the church. I have argued that the first basilica failed, in part, because of the struggle to manage this flow of water which likely ran down the slope, across an open courtyard and down the foundation trench of the basilica. The large scale reconstruction of the building in the late 7th (or early 8th) century involved the installation of a large rubble filled pit to the south of the church which would slow the flow of water and allow it to dissipate without pooling against the vulnerable church wall. We sketched out this argument here and will publish it in greater detail this winter.

The plan for Brett’s house was to build a drain along the south, alley side, of his garage that would catch the surface run off before it entered and pooled in his garage. This involved digging a trench and a reservoir with … a mini backhoe and filling this excavated area with cobble and gravel (and maybe drain tile).

We did not dig this trench in a stratigraphic way nor did we sieve or carefully examine the material from the trench itself. That being said, the trench did reveal some interesting stratigraphy and some interesting objects, that I’ll post here in a future post.

The upper most level of the trench, the surface, was the packed gravel the is the common road surface for most alleys in Grand Forks. This layer was approximately 2 or 3 inches. Since we excavated on Bret’s property rather than in the alleyway, it seems likely that this level was part of the spill from the alley surface carried toward Bret’s garage by the flow of water, rather than the surface itself which I would imagine to be a good bit thicker. Below that was a layer of what appears to be soil that is about 4 or 5 inches in depth. Like the gravel surface in this area, I assume that this is slope wash.

Beneath this level, however, was 3-4 inch think level of black, charred material which included chunks of coal and what appears to be charcoal. This level appeared after scraping back the top levels as a couple of small patches:     

But as our excavation continued it became clear that this was a level that extended for the entire length of the garage, 50 ft or so. It included many small pieces of window glass, table ware, bottles, as well as other material that suggests domestic discard. It was heavy, black, and burnt. The black level is visible in the photo below.

Bret’s four-car garage was likely built in the 1940s or 1950s, but a smaller garage, probably an carriage house, existed on its footprint as early as 1897 according to Sanborn Maps for the neighborhood. This heavy burnt and coal-laced layer appears a bit deeper on the east side of the trench than on the west, but we didn’t measure it. The garage is evidence that an alley existed behind the house as early as the 1890s when this block (the Renkells Addition) first appears on the Sanborn Maps. Bret’s house is probably a few years earlier than that, and it may be noted on the Sanborn map from 1884 as one of the “5 dwgs, 2 barns.”

On the western side of the trench, we excavated four foot deep reservoir. This revealed a 9 inch deep layer of soil below the burnt and coal. I would assume that this level represented a flood deposition at some point in the property’s history but it was below the level of the current garage so it likely pre-dated 1950s (perhaps it can be associated with the flood of 1897). Below it was a very clear, 2 inch thick surface of sand and clay. It’s visible as a light level in the photo below.

I’m guessing that this was an early road or alley surface in the area, but without digging more, I am not entirely sure. Our rather careless backhoe excavation of this pit made it hard to isolate any particular context; moreover, there was a metal anchor of a “guy-wire” which presumably supported a now removed utility pole in the area. It was anchored below the sand and clay surface which suggested either that the surface was compromised by the installation of the anchor or that this anchor was associated with this level. 

The burnt, black coal level is baffling to me. It looks like the debris from a coal bin or the cleaning out of a furnace. Perhaps the unburned coal, clinkers, and ash were dumped in the alley way along with other household trash and over time developed into this substantial deposit. Are there parallels for this elsewhere?