This database  ([AKA] N.A.G.B.A.D. )
NORTH AMERICAN BEDROCK INFERENCE DATABASE)
shows the geological age of bedrock and the type/ origin of rock

>Sections or this map created from 231 images based on rock core tests
>map shows bedrock from 46 states
>for google earth and google pro. 
>map can be accurate by 20 miles

NOT FOR PROFESSIONAL USE

> Sections or this map are missing due to copy right issues