Hamilton Group
![Generalized stratigraphic nomenclature for the Middle Devonian strata in the Appalachian Basin.[4]](/uploads/202501/17/USGS_2006_1237_table2_Stratigraphy_Middle_Devonian.svg0214.png)
The Devonian Hamilton Group is a mapped bedrock unit in New York, Pennsylvania, Maryland, Ohio and West Virginia. In Virginia, it is known as the laterally equivalent Millboro Shale. The group is named for the village of Hamilton, New York. These rocks are the oldest strata of the Devonian gas shale sequence.