vania to this land were for many years a cause of dispute, and several battles were fought for its possession, but a court of arbitration appointed by the Continental Congress awarded it to Pennsylvania in 1782.

For a history of the northern and eastern boundaries of Pennsylvania see New York, pages 113-114, and New Jersey, page 117.

That part of the southern boundary of Pennsylvania which separates Pennsylvania from Delaware, as defined by the charter of 1681, is an arc of a circle of 12 miles radius, having New Castle, Del., as its center. This line was surveyed and marked in 1701 under a warrant from William Penn. (See p. 125.)

According to the original grant of 1681 the boundary between Pennsylvania and Maryland was to be the "beginning of the 40th degree of northern latitude," or what we would now call the 39th parallel of latitude. (See p. 119.) This boundary was for many years in dispute, Lord Baltimore claiming the country along Delaware Bay and River to the mouth of the Schuylkill, which was also claimed by the Duke of York under his grant of 1664. William Penn, in 1682, obtained from the Duke of York a release of his claim, but not until 1760 was an agreement reached with Maryland. Commissioners were appointed in 1732 and again in 1739 to run the line, but they failed to agree, and chancery suits were the result. Finally a decision of Lord Chancellor Hardwick in 1750 was taken as a basis for adjudication, and an agreement was signed July 4, 1760, by which the line between Pennsylvania on the one part and Delaware and Maryland on the other was to be determined as follows:

A due east-west line was to be run across the peninsula from Cape Henlopen to Chesapeake Bay. From the exact middle of this line a line was to be drawn north which would be tangent to the western arc of a circle having a radius of 12 English statute miles measured horizontally from the center of the town of New Castle. From the tangent point a line was to be drawn due north until it intersected a parallel of latitude 15 miles due south of the southernmost part of the city of Philadelphia. This point of intersection would be the northeast corner of Maryland, and from it the line was to be run west on a parallel as far as it formed the boundary between the two Provinces.

In 1760 commissioners and surveyors were appointed, who spent two or three years in measuring the base line and the tangent line between Maryland and Delaware. The proprietors became wearied with the delay and sent from England two famous mathematicians, Charles Mason and Jeremiah Dixon, who verified the work of their predecessors and ran the line between Pennsylvania and Maryland, ever since called the "Mason and Dixon line " and probably the most widely known boundary in the United States. (See fig. 9.) Mason

TYPICAL BOUNDARY MARKS, OLD AND NEW

A, Monument No. 20 on the Mason and Dixon line; B, boundary stone between the District of Columbia and Maryland; C, a Texas-New Mexico boundary stone; D, mark at the northwest corner of Texas.

and Dixon determined the latitude of this line, which they located 15 miles south of Philadelphia, to be 39° 43′ 17.6". That they were skilled and did their work carefully is shown by the fact that by the resurvey, made 130 years later with modern instruments and methods, the position found for the line at the northeast corner of Maryland differed only 2.3" (180 feet) from that determined by them. The later position is 39° 43′ 19.91". (See p. 126.)

Mason and Dixon began work on this line in 1763 but were stopped by Indians in 1767, after having run the line about 244 miles west of the Delaware (230 miles 18 chains 21 links from the northeast corner of Maryland) and thus not quite finishing the work as planned, although it has since been ascertained that they had run about 30 miles beyond the northwest corner of Maryland. The original stones for 5-mile marks on this line were carved in England from oölitic limestone; Lord Baltimore's coat of arms was shown on the Maryland side and the Penn arms on the Pennsylvania side. (See pl. 9, A.) Intermediate milestones were smaller and were marked "M" and "P" only, on opposite sides.

Because of the removal of the stone at the northeast corner of Maryland and for other reasons, it was deemed desirable to resurvey and re-mark the State boundaries in that locality; consequently Maryland (in 1846), Delaware (in 1847), and Pennsylvania (in 1849) authorized the appointment of commissioners to undertake the task. An Army officer was delegated by them to make the surveys, which were completed in 1850. In the resurvey of the arc boundary and of the adjacent lines the surveyor in charge unfortunately disregarded "the well-known rule that an actual line upon the ground is to be preferred to the written description of the same line in a deed." He changed the position of the arc boundary as marked in 1701 and assigned to Pennsylvania the triangular strip 312 miles in length (about 840 acres in area) west of the arc boundary, east of Maryland and south of the Mason and Dixon line, which had previously been assumed to belong to Delaware. This survey was approved by the commissioners from the three States, but no formal action regarding it appears to have been taken by the State legislatures.

8

In 1889 and 1900 the Legislatures of Pennsylvania and Maryland authorized the appointment of a joint commission to "ascertain and re-mark" the boundary between the two States. The field work for this survey was commenced in 1900 and completed in 1903. No changes in the line as run by Mason and Dixon were made; straight lines were run between original monuments, and many new stones

8 For report of the surveyor see Delaware Senate Jour. for 1851, pp. 56-109. of the report and a map are filed in the Maryland Land Office at Annapolis.

A copy

were set on the lines thus established. (See pl. 3, D.) The report of the commission, dated January 25, 1907, was published in 1908 by authority of the Legislature of Maryland and in 1909 by Pennsylvania. These volumes contain a description of each of the 225 boundary monuments, including many of the original stones that were repaired and reset; also a bibliography of manuscripts and documents relating to the line, with more than 2,000 entries.

Positions for a dozen or more points on the Mason and Dixon line have been determined by the United States Geological Survey, some of which are as follows:

In 1889 the Legislatures of Delaware and Pennsylvania authorized the re-marking of the boundary between the two States. The commissioners agreed that the northern boundary of Delaware should run due east from the northeast corner of Maryland to a point 12 miles from the New Castle courthouse and thence follow a curved line passing through as many boundary marks of the 12-mile circle of 1701 as could be identified. The resurvey was made, and 46 marks were set on the arc boundary in 1892-93. The triangular tract assigned to Pennsylvania by the commissioners of 1849 thus reverted to Delaware. The report of the commission and the line as marked by it were "accepted, approved, and confirmed” by the Legislature of Pennsylvania by act of June 22, 1897,10 but were not formally accepted by the Legislature of Delaware until March 28, 1921. The assent of Congress to the action of the States was given on June 30, 1921.11 The land part of the Pennsylvania-Delaware line as determined by this survey is 22.87 miles in length.

Commissioners from Virginia and Pennsylvania agreed in 1779 that the boundary between those States should be fixed as follows: 12 That the line commonly called Mason's and Dixon's line be extended due west five degrees of longitude to be computed from the river Delaware, for the southern boundary of Pennsylvania; and that a meridian drawn from the western extremity thereof to the northern limits of the said states, respectively, be the western boundary of Pennsylvania forever.

For a report of this survey and a historical sketch of the Mason and Dixon line see U. S. Coast and Geodetic Survey Rept. for 1893, pt. 2, pp. 177-222. 10 Pennsylvania laws for 1897, p. 183.

11 42 Stat. L. 104.

12 Pennsylvania Sec. Internal Affairs Rept. for 1887, p. 293. There is a separate volume of boundary maps accompanying this report, Hening, W, W., Virginia Stat. L., vol. 10, pp. 519-537, 1822,