by Robert Leslie Cohen

Extracted from Passaic County Historical Society Newsletter, 2008 Volume: 9, No: 1

I really think if Gentlemen of known Character and probity could be employed in making Maps (from actual survey) of Roads, Rivers, Bridges and Fords over them, the mountains and passes through them, it would be of the Greatest Advantage.” – From a 1777 letter to Congress by General Washington.

There had been maps of the area as far back as 1527. The first one depicting the New York-New Jersey area was taken from the exploration of Giovanni da Verrazano when he glimpsed Manhattan from its harbor in 1524. The work known as the Gastaldi Map was published by Ramusio in Venice in 1556. As Verrazano was in the employ of Francis I of France he named the area around present day Manhattan, La Nova Francia. Manhattan is depicted as a peninsula as a storm forced Verrazano away from the area so he wasn’t able to determine that Manhattan was an island. But Hudson on the Half Moon in 1609 and his charts gave a better view of the area and Block’s Map of the Northeast finally depicted Manhattan as an island in 1614 and as time passed maps improved in quality depicting the New York-New Jersey area as well as the rest of the northeast. By the time of the Revolutionary War New York, New Jersey and its environs were very well depicted and quite accurately. But these maps were largely the product of British mapmakers and were used by the British armed forces in its campaign in the area. Thus, the need for accurate maps for the American forces in order to campaign effectively.

Here is where we tum to Robert Erskine. He was born in Dumfermline Scotland in 1735. The young man was raised and educated in Scotland. He attended the University of Edinburgh and was trained in engineering. After some business dealings in England he emigrated to the Ringwood, N.J. area in 1771 and replaced Peter Hasencleaver the talented but controversial manager of the American Iron Company headquartered in London England. ln England Erskine also had experience as a surveyor and hydraulic engineer.

Portion of Erskine’s map number 108, “From Col. Deys to the
Ponds and from Wyckoff to Bell Grove.”
(Collections of the New York Historical Society.)

While trying to put affairs of the Iron works in order in 1775 Erskine saw the crisis developing between the colonies and England. With the advent of hostilities in order to protect the iron company from any hostile source Erskine formed a militia company. Though this company while ostensibly neutral even wearing green coats (which were worn by loyalists), he personally felt the American side was just and sided with them. Using his engineering talents, he developed the marine “Chevaux de Frise” a tetrahedron composed of sharpened oak logs that was placed in several waterways in the States in order to disable and stop British ships from advancing. Benjamin Franklin who knew Erskine in England having signed a petition to get him into the Royal Academy, helped place this instrument into the Delaware River.

One of the most pressing needs of the Continental Army as the war progressed was for skilled mapmakers. In July of 1777 al Pompton on a stormy day General Washington who had heard of Erskine’s engineering prowess offered him the position of Geographer and Surveyor General of the Continental Army. This appointment was made official when Congress passed a resolution on July 27, 1777.

Gen. George Washington’s letter to Robert Erskine of August 7, 1799,
asking if roads had been surveyed. (Washington Papers, Library of Congress.)

Erskine immediately set to work by bringing together a staff of assistants. He wanted “young gentlemen of Mathematical genius who have a taste for drawing.” His department set to work making operational maps of the region from the Hudson Highlands to Philadelphia and elsewhere. His unit especially emphasized the northern part of New Jersey from Jersey City westward including Passaic County. Maps were also prepared showing parts of New York, Connecticut Pennsylvania and Maryland. These documents showed “surveyed and unsurveyed roads, foot paths, heights even taverns, and other landmarks.” Washington used these maps in planning his troop movements. While engaged as Washington’s mapmaker Ringwood was headquarters for the Army’s mapmaking agency though Erskine often traveled with the Army. The New York Historical Society has many of Erskine’s maps on file showing areas of New York, Connecticut, New Jersey, Pennsylvania and Maryland. Some of the titles in the collection are interesting and show that the Erskine map makers were concerned with accuracy. Examples of some maps are, “Contraction in the Jerseys 1 mile an inch, From Col. Dey’s to the Ponds & from Wyckoff to Bell Grove and From Elizabeth Town Point to Totowa (2 miles to an inch).” Erskine’s staff was composed of approximately twenty surveyors in addition to chain bearers and other assistants. Maps were first sketched on a plane table. They were then contracted in size in a reduced scale. As this was the 18th Century the maps were given to trained draftsmen who made final copies that included supplemental information from field notes. Copies were made by hand and then distributed to high ranking officers as it was important to keep these documents out of enemy hands. The surveyors work was hazardous as they faced danger from inclement weather, dangerous animals and hostile enemy action. Despite these obstacles the maps were surprisingly accurate.

In September 1780 while Erskine was making surveys in the Hudson Highlands, he contracted a severe cold which developed into pneumonia. He died on October 2, 1780, the same day Major Andre was hanged in Tappan, New York. General Washington attended Erskine’s Funeral in Ringwood.

After Erskine’s death his assistant Simeon DeWitt was appointed Surveyor General. He had been the only graduate in the class of 1776 at Queens College now Rutgers University.