Surficial Geology 1:250,000 (Hosted Feature Layer)

Massachusetts surficial geology data showing the location of sand and gravel deposits delineated atop U.S. Geological Survey 1:250,000 map sheets.马萨诸塞州表层地质数据集，该数据集标注了美国地质调查局（U.S. Geological Survey）1:250000比例尺地图图幅上划定的砂和砾石矿床的位置。