Of course the fortieth parallel was not used, Mason & Dixon ran the (approximate) latitude of 39 degrees 43 minutes, 20 seconds.
The map shows the small triangle of land extending southward between Maryland and the Delaware circle.
Just a section including Pennsylvania is shown here, the state and Philadelphia are named. Size: Sheet - 17 x 23 inches; map - 12.5 x 13.5 inches. AMERICA according to the disposition now made & to be compleated as soon as practicable taken from the general distribution dated at New York 29th. With the alterations to summer 1767 done in yellow. The original printing was in two separate maps: 1) A PLAN OF THE BOUNDARY LINES between the Province of Maryland and the Three Lower Counties on Delaware with Part of The Parallel of Latitude which is the boundary between the Provinces of Maryland and Pennsylvania. This image is from a reproduction of the original published in 1887 by the Pennsylvania Secretary of Internal Affairs in a report that contained maps of all the state boundaries.
The Geographie Moderne was published up to 1793 with many of the same maps. 2) A PLAN OF THE WEST LINE or Parallel of Latitude, which is the Boundary between the Provinces of Maryland and Pensylvania. Only a portion of this large map (76 x 27 inches, scale: 1" = 4 miles) is shown here, the southeast corner of the state on the south by a circle drawn at twelve miles distance from New Castle, northward and westward unto the beginning of the fortieth degree of northern latitude, and then by a straight line westward, as the Pennsylvania charter says.
It depicts the region from the Allegheny Front west to the Sioto River in Ohio.
The second, showing the straight line west, got into the private market and in 2002 sold at auction for over half a million dollars.
The printed versions of the original maps are illustrated in Papenfuse & Coale.
by William Smith, William Bradford, Philadelphia 1765, (London 1766) along with several other maps illustrating the expedition of Henry Bouquet and his battle against the Indians at Bushy Run near Pittsburgh.
It shows routes of march and rivers and is reproduced in Brown #45.