Microfossil Succession in a Bog in Northern Wisconsin

Abstract

A stratigraphical and statistical study of the microfossils in the marginal mat of a small bog lake in Vilas County, Wisconsin, was undertaken in an attempt to determine the plant succession of the region and to test a new method for determining the vertical extent of limnic and subaerial peat in a bog. The deposit in which these observations were made is known to the Wisconsin Geological and Natural History Survey as the Forestry Bog Lake, and is located near its Limnological Laboratory in Section 8, Township 41 North, Range 7 East. The depression in which the lakelet is located was formed by the melting of a buried ice mass in the pitted outwash plain of the Early Mankato Ice (Fourth Wisconsin). The soils surrounding the depression are predominantly sandy, but also contain lenses of gravel. The area of the lake, which is in the center of the bog, is 993 square meters. Its maximum depth is 2 meters. The original area and depth were much greater. Very early in the history of the Forestry Bog Lake there was a connection on the southern side with Trout Lake. How long this persisted is impossible to state, but the condition of the topography suggests that it was very brief and may have been connected only during the melting of the glacial ice at this point. The lakelet (fig. 1) is in the late stage of old age, as is shown by the presence of organic soils, shallow water and an irregular shoreline of peat (Wilson, '35). According to Fassett ('30), the plants growing upon the peat bog are Sphagnum sp., Sarracenia purpurea, Mlonotropa uniflora, Smilacina trifolia, Chioagenes hispidula, Rynchaspora alba, Picea inariana bearing A rceuthobium pusillum, Eriophorunt virginicuiv, Larix laricina, Carex oligosperma, C. pauciflora, C. trisperma, Chamnaedaphne calyculata, Leduni groenlandicum, Gaultheria procumbens, Vaccinium oxycoccos, Menyanithes trifoliata, Kalmia poli* From the Limnological Laboratory of the Wisconsin Geological and Natural History Survey and Coe College. Report No. 64. The publication of the illustrations in this article was provided for by funds other than those of the Ecological Society of America.