An engineer affiliated with the American Cave Conservation Association designed the barricade, which maintains natural environmental conditions. The gate was funded in part by the State Historical Society of Wisconsin. One of the drawings has been directly dated at 1100 years old. Others are thought to represent the period from about A.D. 500 to 1000 based on several diagnostic pottery fragments, the presence of bows and arrows, and styles of deer, which compare with the Effigy Mound Culture. One image may represent a long-horned buffalo and, if so, probably dates to the end of the ice age, nearly 10,000 years ago.
Rock art is very difficult to date.
Drawings and paintings can sometimes be dated using the Carbon-14 method, but this requires removal of some of the pigments. Sometimes carbon contamination from later fires and smoke interfere with the test results. Carvings are particularly difficult to date, since they have no organic material. Archaeologists generally try to estimate the age by cross dating with other styles or artifacts. The deer in the same panel have forked ears with distinct tails, and these are similar to nearby effigy mounds, which are known to have been constructed around A.D. 700-1000.