Sunken history

Eads' ironclad, the Chickasaw, was discovered in the Mississippi over a year ago but will not be raised. I didn't know that:
Archaeologist Christopher Goodwin said there's not much chance any of the shipwrecks will be raised because the cost would outweigh the ships' historical value.
His firm submitted a report on a major discovery in the river, Eads' craft among the finds:
Among the discoveries documented in a two-volume report prepared for the corps by R. Christopher Goodwin & Associates are the remains of a tall-sailed schooner, several river or ocean-going tugs, a number of work and derrick barges, and at least two ferries that once traveled between Algiers and the Walnut Street wharf.
They've been covered in crushed rock, except for the Chickasaw, which is protected but will not be raised.