they salied ashore the missippi river
I think you mean Jeremiah Dixon and Charles Mason. The Mason-Dixon Line loosely separated the North from the South prior to and during the Civil War. It was actually a line between two neighbors, Dixon and Mason in the mid-1700's, and their property dispute is now an American legend.
They had to settle a boundary dispute between Maryland and Pennsylvania
Charles Mason and Jeremiah Dixon were the surveyors who demarcated the Mason-Dixon line between 1763 and 1767. This was done to settle the border issues between British colonies. The agreement to extend the line was made in 1799. The surveyors were Charles Mason and Jeremiah Dixon.
The "old line" refers to the Mason-Dixon Line, which was famously surveyed in the late 1760s by Charles Mason and Jeremiah Dixon. The Mason-Dixon Line marks Maryland's northern border with Pennsylvania and its eastern border with Delaware.
Besides becoming the border between Maryland and Pennsylvania, Charles Mason and Jeremiah Dixon's line became what separated the states that allowed slavery (Confederate; south) and the states that didn't (Union; north)
The effect was Charles Manson and Jeramiah Dixon were hired to map a dividing line of the colonies.
Jeremiah Dixon was born on July 27, 1733.
Charles Mason, Sir George and Jeremiah Dixon traveld through a line which they now call the mason-dixon lien
Charles Mason and Jeremiah Dixon.
Jeremiah Dixon died on January 22, 1779 at the age of 45.
The Mason-Dixon line, named for Charles Mason and Jeremiah Dixon, the surveyors who mapped it out, was originally the border between the colonies of Pennsylvania, Maryland, Delaware, and Virginia (in present-day West Virginia). The line later was extended westwards, marking the border between slave states and free states.
Jeremiah Dixon died on January 22, 1779 at the age of 45.