By far the greater number of mounds were located in Piedmont Virginia, above the Falls of the James. Unlike the Siouan and the Iroquoian, the Algonquian tribes of tidewater Virginia, such as the Powhatans, did not erect earth mounds--at least, as far as present evidence indicates. The earliest white American to have explored scientifically a Virginia mound was Thomas Jefferson. A few years before the American Revolution, he excavated and examined a burial mound on the Rivanna River in Albemarle County, and found it to be a communal grave with an estimated one thousand skeletons laid in distinct strata. The structure was spheroidal in shape, and about forty feet in diameter. Its original height was thought to be twice the height of a man. Such a burial mound was made gradually by covering with earth and stone one skeleton lying on the ground, then placing a second skeleton on top and again covering with earth and stone, until in that manner a thousand burials had been made. A similar mound, but larger, was found beside the Rapidan River, in Orange County. Many earth mounds have been found west of the Shenandoah River. Within this burial mound classification may be included the "cairn," a Gaelic name meaning "the heap," and comprising a grave under a small pile of stones. The largest of such rock heaps is said to be fifteen feet in diameter and three feet high. Several small cairns have been located on the banks of the Rivanna. As for platform mounds, it was the custom of the Cherokee tribe to erect such elevated earth forms as sub-structures or bases for wooden temples or council chambers. As has been already indicated, some Cherokees lived in the land of Virginia, notably in the vicinity of the Peaks of Otter, in Bedford County. Further south, as far away as Georgia, some platform mounds are immense, man-made hills, formerly covered with smooth, polished, hard clay, which at times reflected the rays of the sun. Great buildings once stood upon the summits of those mounds. Because none have hitherto been discovered in the Cherokee area of Virginia does not mean that none existed. And the same can be said of the Cherokee effigy mounds. An effigy mound is one built for religious purposes, generally in the shape or silhouette of an animal or bird; but as yet, none has been discovered in Virginia. The probability that there were effigy mounds is strong. iii. DWELLING-HOUSES Contrary to popular belief, the Indians of Virginia were not a tent people. They lived in wigwams, which are _houses_. Tents belonged to the natives of the Great Plains, like the Sioux Indians. Among the various types of wigwams there are two chief kinds: the circular or "beehive" dwelling, and the rectangular or "arbor" house. Both of these names were given by the English settlers because the buildings resembled constructions in their own homeland across the sea.