The soils of Thoreau's Walden bean-field are called Windsor and Hinckley sandy loams. Laid down by the receding ice sheet into Glacial Lake Sudbury around 10,000 years ago, they are very loose and therefore drain very rapidly. Thus, when it rains the precipitation percolates almost immediately into the underlying glacial deposits. During the driest time of the year in New England (July and August) such soils usually are so dry that crops would wilt unless they were irrigated. In colonial times, watering crops would have been prohibitively expensive, not to mention both Thoreau's and our time. Thus, woodland--Walden Woods--persisted around Walden Pond, giving Thoreau a ready-made wilderness retreat a mere mile and a half from his home in the intensively farmed village of Concord, Massachusetts.