Modeled Top of the Saddle Mountains Basalt Geomodel Unit (smtop_f)
The smtop_f grid represents the modeled elevation of the top of the Saddle Mountains Basalt 
geomodlel unit at a 500 foot resolution. It is one grid of a geomodel that consists of eleven grids 
and a spatial extent polygon shapefile.  As part of a U.S. Geological Survey Groundwater 
Resources Program study, a …