My field school moved from the prairie of western Minnesota to an island in the Great Lakes for our second project of the summer. We are collaborating with James Myster of the US Fish and Wildlife Service on his investigation of a lighthouse ruin on Plum Island just off the tip of Wisconsin’s Door Peninsula.
Plum Island is on the infamous Porte des Morts passage or ‘Death’s Door’ – a waterway linking Green Bay and Lake Michigan. Ships traveling around the Door Peninsula preferred the short-cut south of Plum Island, but too frequently encountered dangerous conditions. More shipwrecks are found in and around Death’s Door than any other freshwater route in the world (Hoffmann 2003).
The U.S. Lighthouse board decided the passage needed a light. They acquired Plum Island in 1848 with construction of a lighthouse completed in 1849 (Foss n.d.). The first lighthouse keeper, William Riggins, lived in the lighthouse with his wife and three children until 1857. The Port des Morts light, however, was placed too far west. Navigators complained and a new lighthouse was built in 1858 on nearby Pilot Island. Once abandoned, the Plum Island light quickly fell into ruins, with its roof collapsing by 1863. A postcard of the ruin dated to around 1907 shows tall walls of rough limestone blocks with openings for windows. The walls were mostly collapsed piles of rubble by the time we arrived on the site.
Our research goals were primarily exploratory. We wanted to map the site, locate the walls, better determine the size and configuration of the original lighthouse, and recover artifacts related to the lives of the lighthouse keepers.
Working on Plum Island was a real treat. We commuted each day by boat from Washington Island. Our boat captain, Lew Clarke, is an experienced mariner (and lawyer). He brought us back and forth each day – docking at the Coast Guard Life Saving Station on the island’s north side. A short 20 minute walk through the woods took us from the dock to the work site. We spent our lunch break either in a flower filled meadow or on a beautiful white pebble beach.
The west wall and northwest corner were the only intact walls still standing above the rubble when we started our site work. In a clever observation, James noted that the intact west wall was about 15 to 16 feet long. Assuming that the main room was probably twice as wide as it was deep, he measured 30 feet from the intact northwest corner and quickly found another intact corner under the northeast rubble pile. The building’s outline was beginning to take shape.
Further investigations of the northeast rubble uncovered additional walls. We found one wall while excavating a 1×2 m trench on the west side of the site (the N18 trench). We suspect that this wall is either a part of the light tower or perhaps a side room attached to the lighthouse’s main room. Tracing the wall, we eventually connected it with the main room, but also found a small box-like ‘room’. The purpose of this box-like addition is hard to determine, but perhaps it is a part of the fireplace for the main room – or maybe it is part of the tower structure. To me, it is exciting to just know that there are intact building walls preserved under the rubble and buried in the ground. It’ll take more work, however, to uncover the rest of the east side architecture and better determine the configuration of the buildings.
The N18 trench also produced artifacts. According to my students, the finds came from outside the wall – suggesting the east yard may have been used for garbage disposal. The finds include a variety of domestic refuse like animal bones and fragments of glass bottles and ceramic dishes. There were also some architectural remains – nails and window glass. Personal items included buttons and pieces of a clay smoking pipe.
A larger artifact assemblage came from our 1×2 m trench off the north wall (E 25 trench). We placed this trench in this location because we had noted glass fragments on the surface. If we wanted a lot of glass sherds, then this trench was brilliantly located. Each 50×50 cm quad produced hundreds of glass fragments – both flat ‘window’ glass and curved glass. The curved glass was most interesting – there are an extraordinary number of thin glass fragments that we think are from kerosene lantern chimney globes. It appears that the lighthouse keepers were either very clumsy with their lanterns or perhaps discarded a stash of extra globes when they moved to their new lighthouse on Pilot Island. One of my goals for the lab is to figure out a ‘MNI’ for the globes. I’m curious as to how many we actually recovered.(A side note – apparently the late 1840s to late 1850s was a time of rapid change in lantern fuel with a switch from whale oil to kerosene, with the first ‘modern’ kerosene lantern invented in 1853. It’s interesting to think that the light keepers were living on Plum Island during this time. Makes me wonder what fuel they used for their lanterns and the tower light. Did they use whale oil in 1848 and kerosene in 1858? Did they spill much of the fuel around the site? Is there a marine mammal soil chemistry signature at the site?)
The results of the fieldwork were exactly what I wanted. We managed to find answers to some of our questions, but we also generated a bunch of new questions – enough questions that James wants us to return next summer for another field season.
We’re in the lab now. My next post will be about the finds.
Foss, Matt (n.d.) “Saving the U.S. Life Saving Station on Plum Island”. Unpublished manuscript available at the Friends of Plum and Pilot Islands. http://www.plumandpilot.org/PlumandPilotIslandsInc/Blog/Entries/2011/2/15_Historian_Matt_Foss_Shares_Findings_files/savingtheplumislandlifesavingstation.pdf (accessed 7 July 2013).
Hoffmann, Gregg (2003) “Beyond Milwaukee: Death’s Door Strait”. http://www.onmilwaukee.com/visitors/articles/deathsdoor.html (accessed 6 July 2013).