82 ILLINOIS STATE ACADEMY OF SCIENCE 



Testimony is lacking as to whether or not these died before 

 the artificial draining of the bog. Ilex verticillata and Pyrus 

 arbutifolia are abundant, and a few clumps of sphagnum 

 have been found on the floor. On the other hand the pres- 

 ence of several more mesophytic families including Osmunda 

 regalis and Aspidium spinulosum, also Solanum dulcamara, 

 and even Maianthemum and one or two small trees, includ- 

 ing oak and mountain ash, indicate that the bog was mature 

 and conditions had become quite mesophytic even before it 

 was drained. 



3. Volo Bog. — The depression in which this bog is sit- 

 uated is located near the center of Section 28, T. 45 N., R. 

 9 E., about one and three-quarters miles northwest of the 

 town of Volo. This depression also is oval with its largest 

 diameter north and south and with two connecting valleys 

 or extensions, one to the southwest and the other curving 

 around to the northwest and west. The depression is ap- 

 proximately three-quarters of a mile in length by one-half 

 mile in width. It is surrounded by ridges of morainal 

 gravel averaging about fifty feet above the floor of the 

 valley, and like Cedar Lake the surrounding slopes show evi- 

 dences of lake erosion at a previous stage of high water. 

 The depression drains from the southwest corner into Sul- 

 livan Lake situated about a quarter of a mile distant. 



The south end of the depression has a level floor of glacial 

 clay, in one place rising into a hillock about one hundred 

 yards in length by fifty in breadth covered by an open stand 

 of oaks, mostly white and ellipsoid. Fig. 3. This clay floor 

 is covered with water to a depth ranging from one to three 

 feet at different seasons. The vegetation is pronounced tus- 

 sock formation with scattered Betula pumila and occasional 

 clumps of willow. This formation covers approximately 

 one-third of the depression and gives way rather suddenly 

 to a mature tamarack forest bordered by a shrub zone con- 

 sisting of chokeberry and swamp sumach. The latter is es- 

 pecially prominent and forms the largest growth of this 

 shrub which the writer has seen in this region. Fig. 4. 

 The floor of the tamarack forest is still slightly quaking and 

 the undergrowth is made up largely of sphagnum and cran- 

 berry with frequent pitcher plants and some blueberries. 



