The bottomland areas of the Reservation are mainly grassland and no old stumps remain to indicate that trees were formerly present. Nevertheless, it might be expected that under original conditions these bottomland areas supported forests, as the soil is deep and rich with abundant moisture. Also most of the early accounts agree that forests occurred mainly along stream courses in this region. Presumably these areas were cut over early, because they were most accessible, and because they supported the best stands of timber. One of the best indications of the former vegetation on these bottomland areas is provided by old bleached shells of snails and certain other mollusks, brought to the surface by plowing in cultivated fields adjoining the Reservation on the south and west (Fitch and Lokke, 1956). A high proportion of the shells are of species limited to humus soil, decaying logs, or leaf litter in moist woodlands (_Stenotrema leai_, _Retinella electrina_, _Zonitoides arboreus_, _Vertigo ovata_, _Helicodiscus parallelus_), to wet places (_Lymnaea parva_, _Succinea avara_) or even to standing pools (_Physa hawni_, _Helisoma trivolvis_, _Pisidium compressum_). No living mollusks could be found in these fields and none could be expected to survive on land that is cultivated annually. As a whole the assemblage seems to be indicative of a humid, poorly drained forest habitat. Presumably most of the shells or all of them are more than 100 years old, antedating the time when the area was first disturbed by human activities, and also antedating the time when the creeks (now 15 feet or more below the fields) had begun to erode their channels. That the shell deposits are of no great antiquity, and represent conditions prevailing within the last few hundred years, is suggested by the fact that all are species still living in Douglas County, and with one exception, all still live on the Reservation. [Illustration: Fig. 3. Tracing from a contour map made in 1914, of the two small valleys on the Reservation, showing changed position of contour lines at gullies by 1952. As a result of overgrazing, and cultivation of part of the upland drainage area, there was relatively rapid erosion in the 38-year interval.] [Illustration: Fig. 4. Map of University of Kansas Natural History Reservation, with 20-foot contours, showing probable approximate distribution of forest in early eighteen hundreds (vertical lines show slopes and hilltops that are still wooded; grid pattern shows bottomlands that were formerly wooded but later cleared for pasture or cultivated crops). Stippled areas show those slopes and hilltops now wooded seemingly as a result of recent reinvasion, that probably were bluestem prairie earlier. Unshaded areas are relatively flat hilltops that are still grassland and are thought to have been bluestem prairie.]