can be dated back in time from the present. There is a distinct change in the color of the varves that occurred around 1800; the lower, older varves are dark brown, and the higher, younger varves are grey. The varves thus record the change in the lakes' environment around 1800, when the primeval forests in the region were replaced by open fields and farmland. The Round Lake National Natural Landmark offers a glimpse of the original forest. See also List of National Natural Landmarks in New York References External links Lakes of New York (state) Meromictic lakes Round Lake Lakes of Onondaga County, New York