We highly recommend finding the Lost Pond as it is worth the walk.
Here's a description of the area:
The Lost Pond Conservation Area is located in the extreme southwest corner of Brookline. It is bounded by the Town's Transfer Station area, the Metropolitan District Commission (MDC) Lost Pond reservation, and the Kennard Park and Conservation Area in Newton.
Lost Pond, a "kettle hole," has developed into a quaking bog on its northern edge. This is one of the most interesting and unusual types of wetlands found in New England. Peat bogs, which often develop in deep glacial lakes, are formed by the gradual decomposition of plant material in highly acidic, poorly drained areas. This peat forms a floating mat over the water and provides a base for acid-tolerant vegetation, which grows in from the edge of the pond. When this mat is walked on, there is a sense of the land "quaking." Peat may accumulate in deposits twenty to forty feet deep. Bogs provide naturalists with excellent data on the ecological history of an area. The underlying peat preserves pollen fossils from the plants that have grown there over the last 10,000 to 15,000 years. Bogs often exhibit very clear belts or zones of vegetation, which change as one moves from the water's edge to the upland. In fact, an aerial photograph of the area reveals a distinct ridge, which was formed by glacial action. This is the dividing line between the uplands and the wetlands and between plants typical of the bog environment and that of the upland.