20230912 15431600 1.0 TRUE Surficial Geology MassGIS has produced a statewide surficial geology datalayer showing the location of sand and gravel deposits. Originally the data were divided into three panels- west, east, and southeast that correspond to the U.S. Geological Survey 1:250,000 map sheets that were used as a basemap. This datalayer is very generalized when compared to the other MassGIS data. MassGIS uses the surficial geology data only to produce volume or area measurements over a large region, e.g. a drainage basin. It is not accurate for site specific analysis.As part of a major data development effort, the datalayer has been greatly enhanced. The data include areas of fine-grained deposits and floodplains. For the original southeast panel, the 1:250,000 Providence, RI sheet, large sand deposits have also been delineated. Additionally, contour lines indicating depth of sand and gravel deposits have also been added.The layer is named SURFGEO250K_POLY. U.S. Geological Survey