Each of the lakes is about four miles long and half as wide. A narrow river, strait, or rapids nearly a mile long connects the two. Originally this rapids was impassable by boats larger than canoes, and even such little craft were likely to be overturned unless handled by strong and skillful canoemen; but some years earlier the state had cleared this passage by removing numerous great boulders and shelves of rock from the bed of the stream so that although the water rushed along just as swiftly as ever, the passage was nevertheless safe for all boats of whatever draught that moved on the two lakes which it connected.