Fig 1.
Location of Calvert Island on the west coast of Canada.
Bathymetric data is shaded from black, representing -1000 metres and deeper to white, representing 0 metres. Bathymetric and coastline imagery is based on information created by SciTech and the Living Oceans Society.
Fig 2.
Chart showing sea level curves from the region around Calvert Island.
The Hakai West curve is specific to Calvert Island and was used to target specific elevations and related time periods for archaeological prospection. Source for curves include Hakai East and West [40], Global Eustatic [51], Cook Bank [54] and Goose Bank [20], see Fig 1 for locations.
Fig 3.
View across the beach at EjTa-4 with Calvert Island in the foreground and Hecate Island in the background.
Photo by Jim Stafford.
Fig 4.
Drone based aerial photograph of EjTa-4 showing the location of the excavation unit with footprints.
Imagery courtesy of the Hakai Institute. The shell midden boundary is based on information provided by Farid Rahemtulla.
Fig 5.
View of the 4 x 2 metre excavation unit.
The 2 x 2 metre square at centre was removed in 2015 to Stratum XII. The 2 x 1 metre units on either side of this, under active excavation of Stratum VII, were removed in 2016. Photo by Joanne McSporran.
Fig 6.
Planview of 4 x 2 m excavation unit undertaken at EjTa-4 showing trackway and track surface.
This illustration is based on field notes and photographs. Radiocarbon dates (cal BP) are from the base of footprint impressions and wood found adjacent to these features on the track surface. All of the bell-shaped pits (shaded grey) are intrusive into the track surface from above with the exception of the rock-lined pit (shaded black) which appears to be stratigraphically associated with the track surface.
Fig 7.
Photograph of track #17 beside digitally-enhanced image of same feature using the DStretch plugin for ImageJ.
Note the toe impressions and arch indicating that this is a right footprint. Photo by Duncan McLaren.
Fig 8.
Photograph of track #15 under boulder.
Arrow indicates outer end of sediment displacement rim. Photo by Duncan McLaren.
Fig 9.
Photograph of track #20 with sediment displacement rim beside digitally enhanced image of same feature.
Photo by Duncan McLaren.
Fig 10.
Two modern gumboot footprints in mid intertidal zone at EjTa-4.
On right–one tide cycle old, note the displacement rim. On left–fresh track not yet subjected to high tide. Also, note the sandpiper tracks in the foreground. Photo by Joanne McSporran.
Fig 11.
Track number #22 showing sediment displacement rim around distal end of the foot.
Digital contrast adjustment (D-stretch) shows the heel and sediment displacement rim parts of the track clearly. Photo by Joanne McSporran.
Table 1.
Measurements and comments on footprints found at EjTa-4.
Length is along the central axis and width refers to maximum width of the ball of the foot. Depth below datum is indicated as DBD.
Fig 12.
Scattergram comparing length and width for the 18 tracks with full measurements.
Three clusters emerge revealing that the prints were left by at least three different individuals. Variation in track size is expected as a result of slippage, foot rotation, taphonomic factors and measurement error.
Fig 13.
Photograph showing the relationship of site stratigraphy to the track surface.
(A) dense grey clay (XI), likely glacial marine–predates 13,400 cal BP, (B) dense brown clay paleosol (X) with preserved wood dating between 13,317 and 12,633 cal BP, (C) track #15, (D) track #17, (E) track #20, (F) superimposed tracks 14a and 14b (G) track #13, (H) bell shaped pit, (I) bell shaped pit, (J) boulder deposited sometime after 3000 years cal BP, (K)–drainage trench to facilitate excavation. Note: Stratum VIII was not found in this part of the excavation. Photo by Duncan McLaren.
Fig 14.
Illustration of strata and associated radiocarbon ages (cal BP).
Only radiocarbon dates on identified plant remains and charcoal have been included. Base photo by Joanne McSporran.
Fig 15.
Examples of stone tools associated with Stratum X.
(A) illustration of fined-grained quartzite retouched flake tool fragment, (B) photo of in situ medium-grained andesite core, (C) rough-grained quartzite retouched spall tool oblique view, (D) platform view, (E) ventral view. Illustrations by Jenny Cohen (A) and Joanne McSporran (C-E). Photo by Joanne McSporran.
Table 2.
Radiocarbon ages, calibrations and stratigraphic relationships.
All radiocarbon ages were calibrated using Calib 7.0.2 and the IntCal13 curve [65].
Fig 16.
Pinus contorta twig sampled from the base of Stratum IX sediment which overlies the track surface.
This wood was dated to 12,640–12,576 cal BP. The underlying light brown clay is the track surface (Stratum X) and under that is grey clay (Stratum XI).
Fig 17.
Illustration of site formation processes based on stratigraphy and radiocarbon dates.
Fig 18.
High intertidal pool near EjTa-4 and present-day features of the upper intertidal zone analogous to those described in the site formation processes for Strata IX—VI.
(A) upper intertidal bell-shaped pool, (B) rill erosion caused by run-off, (C) steeply eroded interrill, (D) 20 cm scale, (E) dunegrass on top of high tide beach berm, (F) driftwood rootball, (G) western redcedar (Thuja plicata) forest. Photo by Duncan McLaren.
Fig 19.
Photograph showing track #4 which has discernable toe drag marks.
This track was later pedestalled and removed to the lab. (Photo by Joanne McSporran).
Fig 20.
Photograph showing track #26 with an elongated heel as a result of the pedestrian slipping forwards while walking in the clayey substrate (Photo by Joanne McSporran).
Fig 21.
Diagram showing the relative percentage of track azimuth measurements.
It is clear from this diagram that those who left the tracks were primarily facing and/or moving in a north to northwesterly direction.