“City Island is a small island and a neighborhood approximately 1.5 miles (2.4 km) long by 0.5 miles (0.80 km) wide. At one time it was incorporated within the boundaries of Pelham, Westchester County, but it is now part of the New York City borough of the Bronx. As of the 2010 census the island had a population of 4,362.

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Most businesses are clustered along the central City Island Avenue. There are two small supermarkets, a gas station, a pharmacy, a bank, a hardware store, and a variety of other small shops. The island is most famous for its numerous seafood restaurants and antique stores, which line both sides of the avenue.

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City Island was created by glacial deposits at the end of the last ice age. There is a layer of bedrock and then a thick layer of red clay topped with sand, with topsoil above that. The southern end has deposits of rare blue clay. The area is strewn with glacial erratic boulders. Local bedrock is Manhattan schist with glacial striations.”

CITY ISLAND WIKIPEDIA