Modeled Combined Extent of All Columbia River Basalt Units (CRB_extent4xconnections)
This shapefile was created as a boundary for the Columbia River Basalt extent and a buffered version 
was used to clip the geomodel unit grids.  As part of a U.S. Geological Survey Groundwater Resources 
Program study, a three-dimensional geomodel was constructed for approximately 53,000 mi2 of the 
Columbia Plateau …