The map’s text includes a description of the colony of Rhode Island at the time as viewed by a British functionary (a transcription and more discussion of the map are available at the Gaspee Virtual Archives):
Idyllic descriptions of New World fecundity (“Fish of all kinds are in the greatest plenty and perfection. The horses are boney and strong, the Meat Cattle and Sheep are much the largest in America, the Butter and Cheese excellent, and every necessary of Life in Attendance”) are balanced against cultural condescension (“It has a Town House, Market House, Library and a spacious Parade, but there is few private Buildings in it worth notice”). The colony’s notable religious tolerance is also pointed out.
The map also includes details of military importance:
Not exactly Here Be Dragons, but similar in its way. The map also lists gun batteries (with the number of guns and size of cannon balls—18 or 24 pounds—they fired), principal farms and farm owners in the colony and soundings throughout the Bay. (Someone with the time might compare the soundings in 1764 with more recent numbers.)
A copy of the map in the David Rumsey Collection is, like this one, divided into 16 sections and mounted. The Rumsey copy includes images of the slipcase in which the sections were originally housed.
* Based on a letter presumably written by Robert Melville and reprinted as “A British Navy Yard Contemplated in Newport, R.I., in 1764.” in The Rhode Island Historical Magazine, vol. 6 (1885-6), pages 42-7. In the letter Blaskowitz is referred to as “Mr. Charles Blaskerwich” and described as “an able surveyor,” although young.