Geology 162 Massachusetts 58 Massachusetts History 53 Water quality 51 Groundwater 43 Groundwater Pollution 40 Historic sites 35 Ocean bottom 35 Stream measurements 35 Water-supply 35 Groundwater flow 29 Stellwagen Bank National Marine Sanctuary (Mass.) 26 Hydrogeology 25 Streamflow 23 Submarine topography 23 Cape Cod National Seashore (Mass.) 22 Geology, Stratigraphic 20 Hydrology 20 Water Pollution 20 Wild and scenic rivers Law and legislation 20 History 18 Homes and haunts 18 Wildlife refuges 18 Groundwater Quality 17 National parks and reserves 17 Marine sediments 15 Aquifers 14 Buildings 14 Contaminated sediments 14 Landscape assessment 14 Massachusetts Politics and government 14 Water quality management 14 Groundwater flow Mathematical models 13 Historic sites Law and legislation 13 National parks and reserves Law and legislation 13 Puritans 13 Salem Maritime National Historic Site (Mass.) 13 United States History 13 Continental shelf 12 Environmental monitoring 12 Historic buildings Conservation and restoration 12 Landscape protection 12 Salem (Mass.) History 12 Water quality Measurement 12 Boston (Mass.) 11 Connecticut 11 Families 11 Geology, Structural 11 Witchcraft History 11 Lowell National Historical Park (Lowell, Mass.) 10 Rivers 10 Saugus Iron Works National Historic Site (Saugus, Mass.) 10 Trials (Witchcraft) 10 Witchcraft 10 Adams National Historical Park (Quincy, Mass.) 9 Massachusetts Bay (Mass.) 9 Polychlorinated biphenyls Environmental aspects 9 Post office buildings 9 Sediments (Geology) 9 Trails 9 Wildlife conservation 9 African Americans 8 Authors, American 8 Cultural landscapes 8 Floods 8 Great Meadows National Wildlife Refuge (Mass.) 8 Historic buildings 8 Marine pollution 8 Pilgrims (New Plymouth Colony) 8 Rhode Island 8 River sediments 8 Runoff 8 Water withdrawals 8 Assabet River (Mass.) 7 Borings 7 Boston (Mass.) History 7 Excavations (Archaeology) 7 Historic sites Conservation and restoration 7 Land titles Registration and transfer 7 Murder 7 Natural history 7 New Bedford Whaling National Historical Park (New Bedford, Mass.) 7 Trials, litigation, etc 7 Vegetation monitoring 7 Volatile organic compounds Environmental aspects 7 Assateague Island National Seashore (Md. and Va.) 6 Auditing 6 Blackstone River Valley (Mass. and R.I.) 6 Fire Island National Seashore (N.Y.) 6 Friendship 6 Gateway National Recreation Area (N.J. and N.Y.) 6 Hazardous waste sites 6 Longfellow House-Washington's Headquarters National Historic Site (Cambridge, Mass.) 6 Massachusetts Antiquities 6 Ponds 6 Saltwater encroachment 6 Sewage Environmental aspects 6 Stream-gaging stations 6 Trials (Murder) 6 United States Politics and government 6