- a substratum.
Origin of understratum
Examples from the Web for understratum
Historical Examples of understratum
Where the city is now built it is fine siliceous sand, supported by an understratum of clay, which is of varied colors.Petals Plucked from Sunny Climes
But there is an understratum of deep, calm sea, which the breath of the wildest tempest can never reach.The Life and Public Services of James A. Garfield
Emma Elizabeth Brown