The head of Chesapeake Bay, on either side of the Susquehanna River, is composed of various broad estuaries, with small streams entering them. To the eastward the chief is Elk River, and to the westward are the Gunpowder and Bush Rivers, with others. Not far above the Severn is the wide tidal estuary of the Patapsco, so named by the Indians to describe its peculiarity, the word meaning "a stream caused by back or tidewater containing froth." A few miles up this estuary is the great city and port of the Chesapeake, Baltimore, so named in honor of Lord Baltimore, and containing, with its suburbs, over six hundred thousand people. The spreading arms of the Patapsco, around which the city is built, provide an ample harbor, their irregular shores making plenty of dock room, and the two great railways from the north and west to Washington, which go under the town through an elaborate system of tunnels, give it a lucrative foreign trade in produce brought for shipment abroad. From the harbor there are long and narrow docks, and an inner "Basin" extending into the city, and across the heads of these is Pratt Street. This highway is famous as the scene of the first bloodshed of the Civil War. The Northern troops, hastily summoned to Washington, were marching along it from one railway station to the other on April 19, 1861, when a Baltimore mob, sympathizing with the South, attacked them. In the riot and conflict that followed eleven were killed and twenty-six were wounded. A creek, called Jones's Falls, coming down a deep valley from the northward into the harbor, divides the city into two almost equal sections, and in the lower part is walled in, with a street on either side. Colonel David Jones, who was the original white inhabitant of the north side of Baltimore harbor, gave this stream his name about 1680, before anyone expected even a village to be located there. A settlement afterwards began eastward of the creek, known as Jonestown, while Baltimore was not started until 1730, being laid out westward of the creek and around the head of the "Basin," the plan covering sixty acres. This was called New Town, as the other was popularly termed Old Town, but they subsequently were united as Baltimore, having in 1752 about two hundred people.