THE START OF APPALACHIAN GEOLOGY: 1836, FIRST SEASON OF THE PENNSYLVANIA GEOLOGICAL SURVEY

In the early 1800’s, the known geology of Pennsylvania (PA) was scattered, minimal in detail, and often incorrect. A few short papers about PA geology were presented at the American Philosophical Society and the Academy of Natural Sciences in Philadelphia. In 1832, 7 men organized the Geological Society of PA. This society encouraged geological study, published articles, and pressed the PA legislature for a state geological survey. On 3/29/1836, a PA legislative act created the first PA Geological Survey with an annual expenditure of $6,400.00 to pay the salaries and expenses of a geologist, Henry D. Rogers, two assistants, James C. Booth and John F. Frazer, and a chemist, Robert E. Rogers. The primary purpose of the Survey was to learn more about the distribution of coal and iron ore in PA.

Rogers first initiated several traverses across the state in order to ascertain where to concentrate further study. This early evaluation led to subdivision of PA into 3 regions: southeastern, middle, and northwestern. Rogers then named the middle area the Appalachian region and the northwestern area the Allegheny region.

The most enlightening work of the 1836 season was that of Frazer who went to Bedford County and made a stratigraphic traverse from the Pennsylvanian coal measures in the Broad Top coal field at Hopewell downward along Yellow Creek and its prolongation Sandy Run through the water gaps in Terrace and Tussey Mtns. to the Lower Silurian limestones in Morrison’s Cove. This crossing of 25,000 feet of rock was unique because it is one of the few lines of one-dip section in the folded Appalachians. Frazer’s findings were subsequently verified by Rogers along Yellow Creek and Booth along the Potomac River. The critical clarification was the separation of the Tuscarora (Silurian) and Pocono (Mississippian) rocks that had previously been confounded together.

As Lesley (1876) so eloquently stated, “we may consider that then the general geology of Pennsylvania and of the Atlantic states was settled. It has, in fact, suffered no modification of any great significance since that time.” In addition, with proper stratigraphic succession known, Rogers clearly recognized and identified the Appalachian anticlines and synclines and American structural geology commenced in 1836.