HAMPSHIRE FORMATION

  Site Locations: 

Indigo Tunnel, mileage 137.80

        Nearest Access: Pearre/Lock 56, mileage 136.21

Town Creek Aqueduct, mileage 162.0

        Nearest Access: Lock 67, mileage 161.67

  The red sandstone and siltstone layers of the Hampshire were deposited in a subaerial oxidizing environment, perhaps deltaic or marginal mudflats to an emerging or shrinking depositional basin.  The Hampshire represents a respite from the thick marine, fossiliferous deposits that are both immediately older and younger.  Along the Canal, it is not fully exposed, although downstream of Town Creek Aqueduct the abandoned railroad provides fair opportunities to observe it.  The Hampshire dominates the landscape across the river in West Virginia where it is exposed for almost a mile along the railroad downstream from the community of Paw Paw.

  Some of the Hampshire layers near Indigo Tunnel exhibit mudcracks and ripple marks, the latter indicative of very shallow water deposition.  Additional evidence for shallow water is associated with the greenish, thin sandstone layers that differ from the characteristic red beds of the majority of the Hampshire.  Those layers represent times of reduced oxidation of the iron.  Walking from the east portal around to the west portal of the Indigo Tunnel brings one to exposures of the fossiliferous Foreknobs Formation,  signaling a return to a marine depositional environment in this locale.

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