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Outcrop of Basal Conglomerate, Cretaceous Potomac Group

Detailed Description

An outcrop of basal conglomerate of the Cretaceous Potomac Group just east of the Fall Line in central-eastern Virginia.  New geochronologic age control on both the fine-grained sediment and unique volcaniclastic clasts within the deposit shed light on Neoproterozoic rocks that were completely eroded from the Piedmont landscape during the Cretaceous.  The Potomac Group is the largest and most-used Coastal Plain aquifer in the mid-Atlantic states, with nearly 1.6 million people drawing from it in the Hampton Roads area of Virginia. 

Sources/Usage

Public Domain.