Two of Alnwick’s greatest treasures are the unsigned manuscript “A Plan of the Town and Harbor of Boston” above and the rough pencil sketch (next slide), which covers the shaded area in the Plan. Drawn not long after the events, they are the earliest known British maps of the retreat from Concord on April 19, 1775.
In the sketch above, the “Bridge where the attack began” (upper left) is not Concord’s famous “rude bridge,” but another, over Mill Brook, where the retreating redcoats came under heavy fire from the “provincials.” Percy relieved Smith at Lexington (not west of it, as indicated here) and took the lower road, through Menotomy (see the previous slide, also) and Cambridge, rather than the upper fork, as the Plan’s author erroneously thought. On the map, Menotomy is labeled “Monatony,” an Algonquian word meaning "swift running water." (It is now Arlington, Massachusetts.)