ROBINSON FALLS, THE SITE OF THE FIRST RECORDED GEOLOGIC DESCRIPTION IN PENNSYLVANIA, HAS BEEN FOUND NEARLY THE WAY THOMAS HUTCHINS DESCRIBED IT OVER TWO CENTURIES AGO

In J.P. Leslie’s 1876 publication, “Geologic Explorations of Pennsylvania and Other States,” it is reported that the first recorded geological description of any part of Pennsylvania was delivered by Thomas Hutchins to the American Philosophical Society in Philadelphia on January 28, 1786. Hutchins’ 300-word sketch eloquently described the interval exposed under a scenic waterfall, formed in the Benwood Limestone member of the Upper Pennsylvanian Monongahela Group. The section is composed of several feet of calcareous silt and clay shales at the base overlain by increasingly purer beds of limestone, reaching a total height of 22 feet. This waterfall is known today as “Robinson Falls” after James Robinson, who may have operated a mill and a distillery near the falls in 1818. Evidence suggests that Hutchins probably made his observations during the summer of 1784 while helping out with the surveying of the Mason-Dixon Line, but he had earlier opportunities to visit this rock exposure during his travels as a soldier in western Pennsylvania. Hutchins’ attention to detail makes it possible to ascertain with complete certainty that this is the same site he described over 200 years ago. Changes to the landscape in the last 150 years have been substantial in the bituminous coal region, where extensive mining and settlement have occurred; however the area around the site appears to have remained unaltered. The site is located along the western edge of Connellsville, Pennsylvania, on Opossum Run, approximately ½ mile upstream from where it empties into the Youghiogheny River. The falls flow over a rock ledge on which is located the Catawba Indian Warpath that ran from North Carolina to New York. General Braddock used this path on his way to Fort Duquesne, and his army may have camped at the falls. Thomas Hutchins fought in the French and Indian War and was commissioned a lieutenant in the British Army in 1757, and captain in 1763. He remained in the employ of the military until 1779 as an Indian fighter, engineer, surveyor, and mapmaker. In 1781, he was appointed as the first geographer to the United States under George Washington and is credited for the system of platting public lands in 1 mile sided squares. Currently, Robinson Falls is privately owned, and it has been entered into the Pennsylvania Natural Heritage Program as a geologic heritage site.