The Chesapeake & Ohio Canal was designed to run along the eastern side of the Potomac River, creating a navigable route between Cumberland, MD and Washington, DC. By June 1829, the ideal width and depth of the canal had been defined as follows: breadth on the surface of the water of 60 feet; depth of 6 feet; and breadth at bottom of the water of 42 feet. The area of the resulting cross section equaled 301 feet.
In a number of areas north of the Seneca Quarry, the construction of the canal ran into problems due to the cliffs of heavy rock (primarily sandstone) projecting into the Potomac River. Contractors had to blast the canal through the rock and construct embankments to separate the two waterways.
The photograph shows an area of the Chesapeake & Ohio Canal located near Lock 26. Built in 1830, this section of the canal was constructed by a team led by Almon H. Millerd, contractor, and supervised by Herman Boye, engineer. It was taken standing on the embankment – a structure built to prevent the canal from caving in and to protect it from high levels of water in the adjacent river – and looking across the canal at the blasted rock face.