It was a natural step to the third development, the "central-passage" type, a group of buildings named by this writer for the purpose of convenience. A "screen" or wooden partition was added to the end of the "Hall" or Great Room in order to make a passage from front to back in the center of the edifice. In that way the living space, the "Hall," was made more private than when it served as a passageway. At any rate, the brick "Keeling House" (c. 1700), Princess Anne County, is a good specimen. A later, or "Hangover" phase of the central-passage type is "Smith's Fort Plantation," generally known as the "Rolfe House," Surry County, which has been continuously and erroneously dated 1652, but which really belongs to the first half of the eighteenth century. [Illustration: A Cross Plan in Virginia "Bacon's Castle," c. 1650] The last or culminating development in the rural dwelling was the changing of a "hall-and-parlor" habitation, or one of "central-passage" variety, into a "cross-house." The cross was formed by adding an enclosed porch, usually with a "porch chamber" above it, on the front façade, and a wing, like a stair tower, to the rear. However, a "T"-shaped domicile, with no back wing, is also classified as a "cross-house." An old record tells of one Southey Littleton, of Accomack, who had a porch and porch chamber on the front of his dwelling--in other words, a cross-house. Of the extant or partially extant examples in Virginia are "Bacon's Castle" (c. 1650), Surry County; "Malvern Hill" (c. 1662), Henrico County; and "Christ's Cross" (c. 1690) and "Foster's Castle," (c. 1685) both in New Kent. They make a veritable school of building which once must have flourished the length and breadth of tidewater Virginia. With its noted "Bond Castle," Maryland, too, had a school of cross-houses. Of the Virginia examples, "Bacon's Castle," two-storeys-and-garret high, with basement, was built by one Arthur Allen, and was named for the rebel, Nathaniel Bacon, who in 1676 ordered his men to capture the dwelling. "Castle" meant "fort." Its cross-plan incorporated a porch, porch chamber, and stair tower. A low, wooden, curtain and kitchen extension, which is believed to have been seventeenth century in date, formerly stood off the gable on the "Hall" side--an arrangement indicating that the Great Room perhaps also served as a dining room. The curtain was the buttery, or bottlery. [Illustration: Medieval Diamond Stacks in Virginia Plan Bacon's Castle c. 1650 West Gable] But the most distinguishing feature of "Bacon's Castle" is the Jacobean "curvilinear" gable at each end. These gables possess round members--"cuspings"--and steps, built pretty much the same way in which they were made in England and the Low Countries. The chimney stacks are Tudor, three in number, set diagonally on their bases at each gable. Because of the way these chimneys look in plan, we call them "diamond stacks."