This detailed navigational chart shows the shallows, sandbars, rocks, and other directions useful to ship captains trying to navigate their way through Boston Harbor.

Published by the French Dépôt des Cartes et Plans de la Marine, its information is based on a chart by English hydrographer Joseph Des Barres in his ''Atlantic Neptune'' (1777-1781).

Finely engraved and by use of shading and hachuring, the chart also shows, the physical inland terrain. The scale of the map is so large (approximately two inches to a mile) that individual buildings and small tracks of land are defined as well. Clearly marked sandbanks within the harbor occupy present day reclaimed and developed areas.

Relief shown by hachures. Depths shown by soundings.

Prime meridian: Paris.