Roundtop Hill is a mountain in Washington County

Washington County, Maryland

Washington County is a county located in the western part of the U.S. state of Maryland, bordering southern Pennsylvania to the north, northern Virginia to the south, and the Eastern Panhandle of West Virginia to the south and west. As of the 2010 Census, its population is 147,430...

, Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

, southwest of the town of Hancock

Hancock, Maryland

Hancock is a town in Washington County, Maryland, United States. The population was 1,725 at the 2000 census. The Western Maryland community is notable for being located at the narrowest part of the state...

. The elevation at the summit is 1358 feet (413.9 m).

Geography

Unlike surrounding mountains, Roundtop Hill is not part of an extended ridge system, and is only about 2 miles (3.2 km) in length. It is located just under 1 miles (1.6 km) from the crest of Tonoloway Ridge

Tonoloway Ridge

Tonoloway Ridge is a stratigraphic ridge that runs southwest northeast through the U.S. states of Pennsylvania, Maryland, and West Virginia. It reaches its highest elevation above mean sea level of 1,292 feet at a knob on its southern end in Morgan County, West Virginia...

, about 3.5 miles (5.6 km) southwest of Hancock. Its presence causes a large bend in the Potomac River

Potomac River

The Potomac River flows into the Chesapeake Bay, located along the mid-Atlantic coast of the United States. The river is approximately long, with a drainage area of about 14,700 square miles...

, which curves around its eastern slope. Much of the eastern face is part of the Chesapeake and Ohio Canal National Historical Park

Chesapeake and Ohio Canal National Historical Park

The Chesapeake and Ohio Canal National Historical Park is a United States National Historical Park located in the District of Columbia and the states of Maryland and West Virginia. The park was established as a National Monument in 1961 by President Dwight D...

 and the canal bed and tow path pass along the narrow bank at its base.

Geology

Outstanding outcrops of the Silurian

Silurian

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...

 Wills Creek Formation

Wills Creek Formation

The Silurian Wills Creek Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.-Description:The Wills Creek is defined as a moderately well bedded greenish-gray shale containing local limestone and sandstone zones, or more specifically as an olive to...

 and underlying Bloomsburg Formation

Bloomsburg Formation

The Silurian Bloomsburg Formation is a mapped bedrock unit in Pennsylvania, New Jersey, New York and Maryland. It is named for the Town of Bloomsburg, Pennsylvania for which it was first described. The Bloomsburg marked the first occurrence of red sedimentary rocks in the Appalachian Basin...

 are exposed along the old railroad grade at Roundtop Hill. Examples of folding

Fold (geology)

The term fold is used in geology when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in...

, formation of cleavage

Cleavage (geology)

This article is about rock cleavage, for cleavage in minerals see Cleavage Cleavage, in structural geology and petrology, describes a type of planar rock feature that develops as a result of deformation and metamorphism. The degree of deformation and metamorphism along with rock type determines the...

, thrust faulting, and the deformation of bedded

Bed (geology)

In geology a bed is the smallest division of a geologic formation or stratigraphic rock series marked by well-defined divisional planes separating it from layers above and below. A bed is the smallest lithostratigraphic unit, usually ranging in thickness from a centimeter to several meters and...

rocks are visible. About 500 feet of strata are exposed.