Zipping down I-95 in Providence, they’re easy to see: wood and pilings poking through the Providence River below, like the tree trunks of a forgotten forest. But the tens of millions of drivers who barrel past every year never realize they have a prime view of an extraordinary cultural and historical site.

“It’s rare physical evidence of Providence’s heyday as a maritime hub and industrial port,’’ says David Robinson ’90, a URI marine archaeologist who has plotted the remains of more than two dozen vessels in Providence Harbor.

The ships date from the mid-19th century to early-20th century. They spread across 33 acres of Green Jacket Shoal off Bold Point: five steamboats, six sailing ships and 15 barges.

Among them are two 1800s paddle-wheel steamships, each 200 feet long, the Mount Hope and Bay Queen. They date to a time—before cars clogged the roadways—when Rhode Islanders eager to escape the heat took all-day cruises, stopping at cavernous shore dinner halls at Prudence Park, Conanicut Park, Newport and Narragansett Pier for clams and watermelon.

Providence Harbor was an industrial landscape then, Robinson says, dotted with shipyards and marine railways. Many of the vessels were likely abandoned at the end of their working lives.

Underwater archaeologists are taking more notice of ship graveyards these days, since Congress passed a law transferring the titles for abandoned ships in state waters to the states to prevent vandalism and looting. Once Robinson finishes his research, he’ll send his report to Rhode Island Sea Grant, which will pass along his findings to other local groups. Together, they’ll decide what to do with the graveyard: leave it alone, remove the ships, or a combination of both.