There have been no updates on the site for quite a while because I have spent the last six weeks (June 28-August 05, 2005) working at the Wenas, WA mammoth excavation. This was the first season of excavation at the site. The dig was set up as a field school through Central Washington University’s Office of Continuing Education, with participation from the University’s Geography and Anthropology Departments. My participation in the dig was as a member of the field school.

Mammoth left humerus next to the same bone from an adult cow

In February of this year, a construction crew was building a private road to a house on the hill on the south side of Wenas Valley, when the backhoe they were using to create the road-cut struck bone. The bone that they found was determined, after examination by a member of the faculty at CWU, to be the left humerus of an elephant-sized mammal. The excavation field school began in the end of June, with nine students (only two of us from the Geography Department: the rest were archaeology students from the Anthropology Department), three CWU professors, and Bax Barton, a paleoecologist with the University of Washington’s Quaternary Research Center. At the time, the primary objective of the dig was to establish a geologic context for the left humerus that had been found, with finding more bone, and identifying the species of the animal as secondary objectives. One of my tasks, part of establishing the geologic context of the humerus, was to work on the stratigraphy and sedimentology of the site.

Because of the multi-disciplinary nature of the field school, much of the first week was spent in the classroom, where principles and techniques from the various disciplines involved (geomorphology, paleontology, archaeology, stratigraphy, geology, ecology, biology, etc.) were presented to the members of the field school. The time not spent in the classroom during the first week was spent preparing the excavation site for a ground penetrating radar (GPR) survey. The GPR machine only has a clearance of a few three or four inches, so all the brush and grass had to be removed from the site in patches large enough to create two survey grids, something like 20m x 15m, each.

The GPR machine is walked back and forth across the survey site at 50cm intervals, both laterally and horizontally, measuring the rate of reflection of radio waves at depths, in slices across the grid. When the lattice of slice, lateral and horizontal are put together in advanced software, and interpolated, the result is a three-dimensional image, and map slices at various depths, showing spots where reflected returns are higher, or lower than average, suggesting buried materials that reflect radio waves better or worse than the surrounding soil matrix.

Based on vague returns from the GPR survey, an excavation grid was laid out, and two backhoe trenches were dug, at an average depth of 2m, and with a total length of something like 35m, in an L-shape around the East and South of the excavation grid. I spent the better part of five weeks in those two trenches, with Dr. Karl Lillquist, a geomorphologist, and chair of my department at CWU, working out the stratigraphic story of the site, in a way that is both understandable, and defensible.

Mosaic of the North trench stratigraphic drawings.  Click to view a PDF of the Wenas site stratigraphic drawings.  Adobe Acrobat or Acrobat Viewer is required.

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The field school was originally set to be four weeks long. However, Jake Shapley, the field assistant, and the greatest champion of the Wenas dig, pushed for a six-week field school, and it was approved, extending to six weeks before it was advertised. The thinking for the four-week school was that, with only one bone, and no real reason to believe that there was any more at the site, it might be a stretch to fill up even a four-week course. The first three weeks of the excavation seemed proof that there just wasn’t enough to fill up the time. While Dr. Lillquist and I systematically described the site stratigraphy in the trenches, using orange-flagged nails on a 50cm grid to mark boundaries between layers, and while Ryan Murphy, the other member of the field school from the Geography Department, used a total-station (an advanced piece of surveying equipment that uses lasers and prisms to plot three-dimensional coordinates of surveyed points) to map the topography and excavation geography of the site, the archaeology students (with participation from the rest of us: everyone doing their part, especially when large volumes of dirt had to be moved) proceeded to open 2m x 2m excavation units, and dig them down, in a controlled, scientific manner, using archaeology techniques, 10cm at a time, screening all of the dirt from their units, looking for bones or artifacts. The excavation units really turned up nothing but shattered fragments of bone, mostly spongy material, for the first three weeks.

View Southat the Wenas site, up the North trench.

During week four, everything changed. All of a sudden, starting on Tuesday of that week, all of the excavation units started to have large bone. From the fourth week on, a right humerus (possibly a mate to the original left humerus), some possible rib bone, and what might be large pieces of cranial bone, were all uncovered at the site. The finds started to be of a great enough volume that the dig, which was only originally scheduled for four weeks, has been approved for a second field season, and there is talk of third and fourth field seasons.

The last few days of the dig were spent marking the stratigraphies of the excavation units, and marrying them to the stratigraphy of the trenches.

Speaking of the significance of the dig, Bax Barton mentioned that this might be the largest scientific excavation of Pleistocene mega-fauna that has been done in the Northwest. While that may seem to be a rather focused and qualified achievement, it is some kind of contribution.

Photos, diagrams, maps, and more explanation of the results of the dig will be posted here, in a revision to this article, as they are available.