Volcanic eruptions of the Avalonian mass of lava and basalt created a curved chain of islands. Near the middle was a part that would one day be Rhode Island. The Atlantic Ocean would not be formed for another 100,000,000 years. Once it was formed, Rhode Island was formed but what would be the Narragansett Bay was about 50 miles away from the coast.
10,000 years ago Narragansett Bay was formed taking its shape and becoming a saltwater bay when the Atlantic Ocean broke through a glacial moraine.
This was before Nantucket, Block Island, and Martha's Vineyard were islands. All of Rhode Island was covered by ice at one point as thick as hundreds of feet throughout the whole state.
When the glaciers melted, the stone and gravel they carried created parts of Block Island, Nantucket, and Martha's Vineyard. Along with these popular islands, they also made up around 30 other islands making up the Narragansett Bay. The melting of the final glaciers was called the Charlestown moraine. It started in Long Island and came down to the Eastern part of Narragansett Bay.
The climate was much harsher than today's climate, even 1,000 years after the bay was formed. Ice-age averages were the norm and the winters took up most of the year. There was not a lot of edible food in the area and the only animals around were mammoths and caribou.
Indian communities since prehistoric times were living beside the bay. They were here long before the Europeans. It is undetermined whether Paleo-Indians lived near the bay or just hunted there. These Indians were ancestors of the Narragansetts and the Wampanoags. The growing season was less than 3 months .
The Narragansett Bay, along with the rest of Rhode Island, eventually became an attractive place to live. With that and the fact that many English settlers were expelled from Massachusetts because they were too liberal for the Puritans, they found a home in RI. There were many disputes with Massachusetts along with disputed between the founders of the small state, including Roger Williams and Anne Hutchinson.