"The park was established in 1928. It has two glacially formed lakes, and rolling, wooded hills. Green Lake and Round Lake are two of a few lakes in the US that are meromictic. There is no spring or fall turnover as occurs in most lakes, so the surface water of meromictic lakes does not mix with the bottom water. Another meromictic lake is Devil's Bathtub in Mendon Ponds Park. Also unique, is the color of the water, hence the name of the park. Because the lakes are very clear, the green and blue wavelengths from visible light are able to penetrate to a great depth and are scattered and transmitted back to the observer’s eye. Birds Likely Seen: American goldfinches, robins and other thrushes, various types of warblers, woodpeckers, sparrows, whitebreasted nuthatches, chickadees, titmice, indigo buntings, scarlet tanagers, northern orioles."