Active mines and mineral plants in the US. at <http://tin.er.usgs.gov/mineplant/>

Boston Subsurface Project at Tufts University. at <http://bostonsoil.atech.tufts.edu/>

CalTopo - Backcountry topographic maps. at <http://caltopo.com/>

Digital Versions of Older NEIGC Guidebooks (1920-1989). at <http://www.library.unh.edu/digital/category/science-technology>

GRASS GIS. at <http://grass.osgeo.org/>

gvSIG. at <http://www.gvsig.org/web/>

Historical Cadastral Maps and Illustrations. at <http://www.historicmapworks.com/>

The Massachusetts DEP Hydrogeologic Information Matrix. at <http://www.mass.gov/eea/docs/dep/water/compliance/hydromat.pdf>

MassGIS. at <http://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/>

Mindat.org. at <http://www.mindat.org>

Mineral Resources Data System (MRDS). at <http://tin.er.usgs.gov/mrds/>

NASA WorldWind. at <http://worldwind.arc.nasa.gov/>

National Geodetic Survey Data Explorer. at <http://www.ngs.noaa.gov/NGSDataExplorer/>

National Geologic Map Database. at <http://ngmdb.usgs.gov/>

NEIGC Fieldtrip guidebooks for various parts of New England. at <http://w3.salemstate.edu/ lhanson/NEIGC/Guidebooks.html>

OpenJUMP. at <http://www.openjump.org/>

PostGIS. at <http://postgis.refractions.net/>

Quantum GIS. at <http://qgis.org/>

Reading Maps with a Critical Eye: Becoming an Informed Map Reader. at <http://www.maine.gov/doc/nrimc/mgs/mapuse/informed/informed.htm>

Recent USGS Publications for Massachusetts. at <http://pubs.er.usgs.gov/#search:advance/page=1/page_size=100/title=Massachusetts:0>

Scanned "newer" 1:25K topographic maps (from MassGIS). at <http://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic- information-massgis/datalayers/imquad.html>

SearchWell - MassDEP Well Driller Program. at <https://eeaonline.eea.state.ma.us/dep/searchwell/>

Soil survey GIS layers for Massachusetts. at <http://www.mass.gov/mgis/soi.htm>

The U-Mass Geosciences publication series. at <http://www.geo.umass.edu/dept_info/contrib_series/list.html>

UNH Historic Map Library for New England. at <http://docs.unh.edu/nhtopos/nhtopos.htm>

USGS Groundwater Watch. at <http://groundwaterwatch.usgs.gov/>

USGS Publications Warehouse. at <http://infotrek.er.usgs.gov/pubs/>

USGS Topoview. (2014). at <http://ngmdb.usgs.gov/maps/TopoView/>

USGS Water Resources of Massachusetts and Rhode Island. at <http://ma.water.usgs.gov/>

What 7.5' quadrangle am I in?: A PDF of a paper map. at <http://www.geo.umass.edu/stategeologist/Quads_Towns_WS7_34x44.pdf>

What 7.5' quadrangle am I in?: KMZ of 7.5" quadrangles for use in Google Earth. at <http://www.geo.umass.edu/stategeologist/QuadTownsWatersheds.kmz>