This tower and ancillary structures were part of a World War II observation platform. The tower overlooks a narrow 200 yd. long flat island 1/4 mile from the Quabbin shoreline. Dummy bombs were dropped from B-25's stationed, at then, Westover AAF base in Springfield, and the pilots were advised as to their accuracy. The white wooden framed tower building that sat atop the steel structure was removed sometime in the late 60s, to the best of my knowledge.