Kettle hole lakes of glacial origin are of frequent occurrence on the north side of Long Island, New York. These lakes very in size and depth. Long Pond is a kettle hole lake located about eight miles south of Wading River on Long Island. it is an irregularly shaped lake approximately one-half mile wide and one-half mile long at the present time (See fig. 1 for the shape of the lake and the location of the areas which were studied statistically.) There are several small ponds that are cut off now or are in the process of being cut off from the main body of the lake. The small ponds that are now cut off were a part of the lake in 1907 and 1908. Local residents say that the water level of the lake has fluctuated considerably in past years. During the different period of drought, the water level has been lowered and marked invasions of plants towards the center of the lake have occurred. With the return of higher water levels in years of plentiful rainfall many plants that had advanced toward the center of the lake have been drowned and this has resulted in a recession of the zones of vegetation.