Fern Dell Gorge State Natural Area

Fern Dell Gorge SNA lies within Mirror Lake State Park and features a small but spectacular gorge cut into Upper Cambrian sandstone. The narrow gorge is a tributary to the larger Mirror Lake gorge. According to geologic interpretations, Dell Creek eroded the Mirror Lake gorge after the creek was diverted northeastward to the Wisconsin River by the terminal moraine and outwash deposits of the glacier. Thus, the lower reaches of Dell Creek are post-glacial and geologically young, characterized by rock-walled gorges. The vertical cliffs are shaded and moss-covered, but predominantly exposed and dry, with seepages along their bases. The moist, cool microclimate within the gorge is partly responsible for the rich diversity of both northern and southern plant species found within the site. The name “Fern Dell” is quite appropriate and derives from the great variety of ferns including bulblet, lady, fragile, Goldie’s, interrupted, maidenhair, northern beech, oak, polypody, and silvery spleenwort.

The cliffs and lower slopes along Mirror Lake gorge are forested with white pine and red pine. Blueberries, huckleberry, trailing arbutus, and moccasin flower comprise the understory with Labrador tea present on the ledges of east-facing cliffs. Red oak, basswood, and yellow birch dominate the valley floor; red pine, Jack pine, and white oak dominate the dry forest above and along Fern Dell. Fern Dell Gorge is owned by the DNR and was designated a State Natural Area in 2003.  Access is from Fern Dell Road west of the park entrance.