The Sugar Grove Petroglyphs are a group of

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

s in the southwestern part of the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

Pennsylvania Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Ma ...

. Located on an

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficia ...

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

in Monongahela Township near the eastern edge of Greene County, the petroglyphs have been known since at least the 1930s. Due to their value as an

archaeological site An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been, or may be, investigated using the discipline of archaeology an ...

, the petroglyphs have been named a

historic site A historic site or heritage site is an official location where pieces of political, military, cultural, or social history have been preserved due to their cultural heritage value. Historic sites are usually protected by law, and many have been re ...

Creation

It is certain that the Sugar Grove Petroglyphs are the work of a Native American people, although the cultural affiliation of their creators is unknown. Among the cultures that archaeologists have seen as possible creators are the Monongahela or

Fort Ancient Fort Ancient is a name for a Native American culture that flourished from Ca. 1000-1750 CE and predominantly inhabited land near the Ohio River valley in the areas of modern-day southern Ohio, northern Kentucky, southeastern Indiana and western ...

, both of which are known to have inhabited the upper portions of the

Ohio River valley The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...

.Herbstritt, James T. National Register of Historic Places Inventory/Nomination: Sugar Grove Petroglyph Site (36GR5).

National Park Service The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government within the United States Department of the Interior, U.S. Department of ...

, 1980-07-22. In his 1974 monograph ''Rock Art of the Upper Ohio Valley'', petroglyph specialist James L. Swauger argued for a Monongahela-related and proto-

Shawnee The Shawnee are an Algonquian-speaking indigenous people of the Northeastern Woodlands. In the 17th century they lived in Pennsylvania, and in the 18th century they were in Pennsylvania, Ohio, Indiana and Illinois, with some bands in Kentucky a ...

identity of the creators; this conclusion he drew from the presence of carvings that he interpreted as representations of

Ojibwe The Ojibwe, Ojibwa, Chippewa, or Saulteaux are an Anishinaabe people in what is currently southern Canada, the northern Midwestern United States, and Northern Plains. According to the U.S. census, in the United States Ojibwe people are one of ...

religious subjects. Although the Ojibwe never inhabited southwestern Pennsylvania, Swauger believed that the ancestors of the Shawnee shared these subjects as part of a common cultural heritage.

Geology

The petroglyphs were carved into the flat portion of a large outcrop of Dunkard-series

; it rises somewhat more than above the ground on its western side, but its other edges are level with the floor of the surrounding woodland. The petroglyphs are confined to a roughly square area of the stone that measures approximately on each side, although most appear on the eastern side and center of this area.

Carvings

Forty-eight different carvings are present on the sandstone; although most are Native American artwork, a few have been added by vandals since European settlement of southwestern Pennsylvania. Swauger grouped the designs into six categories, as follows: Identification of the various designs has been complicated by

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...

; some designs, especially those that are clustered closely together, have deteriorated and are thus difficult to classify conclusively. Among the most difficult are the carvings that were identified as bird tracks; they may have originally been abstract designs or arrowheads. Likewise, many abstract designs may have been created as identifiable designs, with their present conditions being the result of vandalism, later Native American carvings, or erosion. The most distinctive image on the rock is a large, almost circular animal that appears to be swallowing its tail; due to its unique shape and great size /nowiki>its diameter is approximately /nowiki>, it has been seen as the most important single petroglyph at the site. It has been claimed that the site was damaged by

quarry A quarry is a type of open-pit mining, open-pit mine in which dimension stone, rock (geology), rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some juri ...

ing circa 1950, but the only damage visible in a 1960 survey was small bits of stone that had been chipped away, possibly by vandals attempting to remove individual carvings. A 1982 survey discovered that the site had not changed since the 1960 survey.

Recognition

Locals have long known the petroglyphs as the "Picture Rocks;" its original scholarly recognition was under this name, producing confusion in archaeological records after the site was separately recorded under the name of "Sugar Grove Petroglyphs." The first appearance of the Sugar Grove Petroglyphs in scholarly literature was no later than 1931, when they were given a short appearance in an archaeological survey of adjacent Fayette County. More detailed surveys in 1934 and 1950 led respectively to the publication of detailed drawings of the designs and to formal recognition as an archaeological site. Finding preservation of the designs to be a priority, the

Carnegie Museum of Natural History The Carnegie Museum of Natural History (abbreviated as CMNH) is a natural history museum in the Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by Pittsburgh-based industrialist Andrew Carnegie in 1896. Housing some 22 million ...

arranged for the production of

plaster cast A plaster cast is a copy made in plaster of another 3-dimensional form. The original from which the cast is taken may be a sculpture, building, a face, a pregnant belly, a fossil or other remains such as fresh or fossilised footprints – ...

s of the designs during the twentieth century. Sugar Grove has been seen as one of western Pennsylvania's most important petroglyph sites: although it is smaller than many others, its location has spared it from the fate of many waterside petroglyphs that have been submerged by the construction of major dams, and it has suffered less vandalism than many other sites that occupy dry ground. In recognition of their archaeological value, the Sugar Grove Petroglyphs were listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artist ...

in 1986. They are one of four petroglyph sites in Pennsylvania to have received this designation, along with the Indian God Rock in Venango County, the Francis Farm Petroglyphs in Fayette County, and the Big and Little Indian Rock Petroglyphs in Lancaster County.

Creation

Geology

Carvings

Recognition

References

Further reading