THE LADOGA PETROFORM SITE consists of a well-shaped turtle petroform, and an engraved monolith A small collection of artifacts has been recovered from the surface nearby. This material suggests a wide range of potential association, from as early as Early Archaic (8-10,000 years ago) to Middle Woodland, about 2,500 years ago. Tours to this site take place every other year, and are part of a larger tour embracing several sites in eastern Wisconsin.
High water on the Rock River had prevented us from following up some of the leads until July 13, when Dwight Weiser, Joe O’Hearn, Ronald Hackenmiller, and the writer initiated the survey at the Ladoga Site.
The Ladoga Petroform
Our first priority was to evaluate the effects of flooding on both the petroform and the engraved monolith 20.0 m. to the northeast of it. While huge trees had fallen across the Rock River only a few meters downstream from the petroform, the feature itself remains intact. Brush had accumulated on the southeast quadrant, and signs of high water well above the feature to the north show that it had been submerged. There does not appear to have been any significant damage to the feature, and no distortion due to displacements. This will be further studied by comparing earlier photos with the many taken on this field trip.
On entering the immediate area of the petroform from the cultivated fields just north of it, several clusters of boulders were re-examined. Most of these are probably from field clearing (the field does contain an archaeological site since artifacts have been recovered from it.), but some seem to be placed in a contiguous arrangement and are not piled. Cases have been discovered in which field-cleared stones have been thrown upon pre-existing petroforms. One of the clues to such a case is the “fitting” of boulders to each other, a concavity on one fitting a convex projection on another. Such fitting was observed at these boulder concentrations. Glen Salter’s notes show these concentrations exactly where they are, adjacent to the cultivated field above the petroforms. Many photos of these joined cobbles were taken. Future mapping is required here.
The decorated monolith
Several years ago, a large erratic, some 20.0 m to the northwest of the turtle petroform was found to have an engraving along the top from south to north in the form of a pecked serpent. This pecking followed a linear fault in the rock, a kind of natural zig-zag depression. Such enhancements of natural features are alluded to in rock art terminology as iconic congruence. In this case, the zig-zag was enhanced by pecking and the anterior elements of the serpent image were engraved beyond the natural part to the north. A pecked widening of the image is noted at the head end, the contiguous pecking portraying a solid mass. This solid portrayal is common to Archaic rock art, and denotes a naturalistic/realistic dimension in the artistic conveyance – in other words, it shows real mass, not abstracted as outlining would do. The rock here is an igneous erratic, and more like the “hard rock” sites at Hensler and Observatory Hill in Marquette County. Such formations lend themselves to this type of conveyance, and nearly all the petroglyphs at Hensler are of this type. However, there are no known petroforms at the Hensler Site, nor are there any engraved monoliths.
The lone petroglyph at the Ladoga Site is severely threatened. The flooding and persistent wet conditions have led to the complete covering of the engraving by a dense bed of moist folioce lichen. Removal of this will require special equipment, which we did not have with us. The use of metal tools, for example, might seriously damage the marking. An effort must be made to remove this lichen. It now totally obscures the petroglyph.