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George Wescott Fisher

Publications and source records attributed to George Wescott Fisher.

5 recordsLinked to original sources

The river and the rocks: The geologic story of Great Falls and the Potomac River Gorge

The Great Falls of the Potomac River has figured prominently in the purposes of men since prehistoric time. Long before John Smith reached the falls in 1609, groups of Indians from East and West met at this great river barrier to trade and perform ceremonies in honor of the spirit of the "Roaring Waters". As early as 1754, George Washington visualized the Potomac River as an important avenue of trade and communication with the interior. Records show that with the exception of Mount Vernon, Great Falls was perhaps as intimately associated with George Washington's everyday life as any other place in the country. As first President of the "Patowmack Canal Company," Washington frequently visited the working parties as they constructed the canal and lock system which skirted the treacherous falls on the Virginia side. Matildaville, a town of about 40 acres named after the wife of "Light Horse" Harry Lee and consisting of various dwellings, grist mill, market house, forge, sawmill, and tavern, sprang up along the banks of the canal. In 1802, the Patowmack Company canals were essentially completed, and hundreds of boats plied the river, bringing corn and wheat, coal and limestone, flaxseed and furs downstream from the mountainous region of Cumberland. Many of the boats were sold for lumber in Georgetown, thus sparing the boatmen an arduous upstream journey. After the establishment of the Nation's Capital, Great Falls became a popular scenic attraction for residents and visitors alike. But Great Falls was not always so easily accessible as it is today. In 1845, a newspaper columnist, after praising the beauty and historic interest of the region, added, "... the access to this interesting spot is, on both sides of the river, by the most infamous of roads and the accommodations for visitors anything but what they ought to be!" Visitors to Great Falls now number close to a half million annually and, because of this continuing and mounting interest, the U.S. Geological Survey has joined with the National Park Service in preparing this booklet for better understanding and enjoyment of the Great Falls of the Potomac River.

Maryland, Virginia

Interpretation of aeromagnetic anomalies bearing on the origin of upper Chesapeake Bay and river course changes in the Central Atlantic Seaboard Region: Speculations

On an aeromagnetic map of the Chesapeake Bay area, the northeastern part of the bay coincides well with a deep, “flat” magnetic low, and the upper part of the Delmarva Peninsula east of the bay coincides with detailed magnetic highs; the two areas are separated by a steep, straight gradient that matches the eastern shore of the bay. On the basis of magnetic and geologic evidence, we interpret the Chesapeake Bay magnetic low as a buried Baltimore Gneiss dome, bounded on the southeast by a normal or reverse fault marked by the steep, straight gradient; mafic and ultramafic plutonic rocks probably underlie the southeast side of the fault zone. The flatness of the Chesapeake Bay magnetic low, as opposed to the detail of the anomalies on either side, however, suggests that an abnormal thickness of nonmagnetic sedimentary rocks also coincides with the low. This could reflect a buried Triassic basin or, more probably, a thickened section of Coastal Plain sedimentary rocks deposited in the fault-bounded basin. The present course of the upper part of Chesapeake Bay is probably inherited from the pre-Pleistocene course of the Susquehanna River, but the river's course may have been determined by the fault zone. Thus, this zone and similar en echelon fault zones along strike may explain the sudden change in course of major rivers in the central Atlantic Seaboard region.

Delaware, Maryland, Pennsylvania, Virginia

Aeromagnetic discovery of a Baltimore Gneiss dome in the Piedmont of northwestern Delaware and southeastern Pennsylvania

In the central Appalachian Piedmont the “basement complex” is an assemblage of 1,100- to 1,300-m.y.-old gneisses, migmatites, and amphibolites that crops out in “domes” mantled by younger meta-sedimentary rocks of the Glenarm Series. Aeromagnetic data and reconnaissance field work indicate that a previously unknown Baltimore Gneiss dome, here called the Mill Creek dome, is present in southeastern Pennsylvania and northwestern Delaware. The discovery of previously unknown domes of Baltimore Gneiss has bearing on the thickness, structure, and regional relations of the Glenarm Series.

Delaware, Pennsylvania

A further revision of the stratigraphic nomenclature of the Wissahickon Formation in Maryland

The Wissahickon Formation, the thickest and most extensive unit of the Glenarm Series, was divided into lithofacies several years ago. We suggest revision of two of these lithofacies and addition of another. We also suggest that the term lithofacies be shortened to facies. The added facies, the quartzite facies, is distinguished by metamorphosed orthoquartzites and protoquartzites. It corresponds in part to the former Peters Creek quartzite.

Maryland