SAND AND GRAVEL RESOURCE --
Sand and Gravel Resource Potential, 1989 (1:500,000)
Identifies areas where geology permits the existence of sand and gravel resources
and provides an approximate economic ranking of resource potential.
This layer was derived by assigning qualitative assessments to each outcrop
area in the following publication: Indiana Geological Survey Miscellaneous Map
FGDC metadata: SAND_GRAVEL_RESOURCES_IN