Chepiwanoxet Point

Coordinates: 41°40′24″N 71°26′30″W / 41.67333°N 71.44167°W / 41.67333; -71.44167 Chepiwanoxet is a neighborhood in Warwick, Rhode Island, with an island peninsula in Greenwich Bay, an arm of Narragansett Bay. The neighborhood straddles the Amtrak railroad lines, which lie just east of Post Road. Its boundaries are Neptune Street to the north, Alger Avenue to the south, Post Road to the west and Greenwich Bay to the east. Chepiwanoxet Way, an underpass beneath the Amtrak lines, now serves as the only street access in and out of the neighborhood.

Native Americans, who fished its island and shores, named this area between Post Road and Greenwich Bay "Chepiwanoxet." Settled as a colonial farm in early 18th century, it became a beach resort with hotel and shore dinner hall after the railroad station opened cc. 1837. Small lots were sold for summer cottages to upstate residents and for homes to Cowesett hill estate workers in late 19th century. Before World War I, the Gallaudet Corporation built a causeway to the island for its seaplane factory, with many workers living here. Warwick bought the island in 1994 for a city park.

Geology

Chepiwanoxet (locally called "Chepi") is underlaid by sedimentary rocks of the Coal Age (Pennsylvanian period, about 300 million years old). This rock formation is 60 miles (97 km) long, extending from Hanover, Massachusetts, south to the mouth of Narragansett Bay, and 18 miles (29 km) wide from Providence to Fall River. It underlies the entire Narragansett Bay, including the Providence River, Greenwich Bay, Fall River, the Sakonnet River, plus both East and West passages out to the ocean. Chepiwanoxet and East Greenwich are just inside the western edge of the Rhode Island formation.

The real beginning of Chepiwanoxet Island came as a result of the last great ice sheets, which bulldozed rock and stone from Canada to Rhode Island. Along the way, each glacier gouged up billions of cubic meters of underlying bedrock, and then grounded local and foreign rocks together, creating much of the glacial deposits existing today. When the Earth's temperature rose about 10,000 to 12,000 years ago, the glaciers retreated, when they finally began melting faster than they were moving forward. For extended periods, the ice advance equaled the rate of melt, and piles of sediment were deposited in terminal or end moraines, such as on Block Island and in Charlestown (hills in the southern part of the state).^[1]

The new Bedrock Geologic Map of Rhode Island^[2] gives more details of what underlies the unconsolidated surface material. Chepiwanoxet sits atop the western edge of the Rhode Island Formation of the stratified Narragansett Bay Group of the Pennsylvanian period (between 323 to 290 million years ago). The Narragansett Bay Group rocks are part of the Esmond-Dedham subterrane of the Southeastern New England Avalon zone. Uphill from the Post Road (US Route 1) is the boundary between the Rhode Island Formation and the older Scituate Igneous Suite (granite and diorite/gabbro rock) of the Devonian period (408 to 362 million years ago), which extends westward to the Connecticut border.

Creation Theories

The island was possibly created by a brief pause in the last glacial retreat. Since the land and beach are largely sand (having few native boulders and rocks), it is also likely to have been an outwash deposit, perhaps from meltwater runoffs from the high hills (the Love Lane and Cowesett Hills area) down the gully, (now a marsh swamp).

Key facts

The early bay maps (e.g. Charles Blaskowitz, 1777) clearly show Chepiwanoxet as an island. It became a peninsula, when the Gallaudet seaplane factory was constructed in cc. 1915. For trucks to reach the factory, fill was dumped into the marsh, making a causeway access which still remains. As a result of blocking water circulation around the island, Arnold Cove gradually silted into a tidal marsh, located on the northwest side of the island. The island is now a Warwick City Park, open to the public.

The Soil Survey of Rhode Island^[3] lists Chepiwanoxet Point and nearby shores as "Hinckley gravelly sandy loam"; a very porous, well-drained soil of glacial origin, which is of poor topsoil quality. The soil type change (to a bit of "Walpole sandy loam", associated with severe wetness) can only occur in the marsh.

Geography

Chepiwanoxet Point is mapped on the East Greenwich 7.5-minute quadrangle. Bedrock and surficial geologic maps for the quadrangle were published by the U.S. Geological Survey and the Rhode Island State Geologist.

References

1. ^ 1976, Dr. Alonzo Quinn: Rhode Island Geology for the Non-Geologist
2. ^ Hermes, 1994
3. ^ Rector, 1981