sentences:  He excavated a straight channel from Sparrows Point out to the mouth of the Patapsco near Seven Foot Knoll Light between North Point and Hawkins Point, which was erected in 1855; this channel, known today as the Brewerton Channel, continues to be the central link in the path into the harbor.In 1865 Maj. William P. Craighill took over as Baltimore District Engineer of the Corps of Engineers.His initial survey of the Brewerton Channel disclosed severe shoaling at the mouth of the river, and he excavated a new channel starting from the older channel at a point just northwest of Seven Foot Knoll and running south to the mouth of the Magothy River, where it turned to the south-southeast and continued to Sandy Point, just north of the present location of the Chesapeake Bay Bridge.