A variation of the palisade method was the twisting and interweaving of the top branches of the tree-posts into a tight mass, in order to discourage climbers. For observation and defense, loopholes at a convenient distance from each other were usually inserted in the walls. Not all Indian palisades were substantial. Perhaps some became too ancient for their own good. Great storms might blow them down on a dark night. At one Siouan village, "the first Puff blew down all the Palisadoes that fortified the town." As a result, some fortifications had their palisades doubled or trebled for strength. Other fortified settlements were erected like a nest of walls, one within the other. [Illustration: Shapes of Indian Fortified Towns in Virginia] Circular towns, like Paski, in Southampton County, Virginia, usually had in the center a ceremonial space firebed. Separate buildings were grouped about that area. In order to protect the inhabitants against attack, the usual entrance in the walls was narrow, so that only one man at a time could enter. Often measuring two-and-a-half feet wide, such a gateway was formed, snail-shell-like, by the overlapping of the ends of the palisade. When the English in Virginia saw such gates, they called them "turnpikes," possibly because the gates carried spears or sharp projections, vaguely resembling the spiked entrances of medieval England. The plan of another circular settlement, "Patawomeke" or "Potomac," in Stafford County, Virginia, is of interest because there were two rings of palisaded posts, not concentric, but with the rings touching each other at one point. The inner ring was about one hundred seventy-five feet in diameter, and the outer two hundred and eighty. Square towns, like the Nottaway settlement, also in Southampton County, usually measured from two hundred to three hundred feet on a side, and had more than one palisaded entrance. Though not yet proven, it is believed that when the Indians employed "flankers," which are side or corner projections, or bastions, in their walls, as they did upon occasion, they copied them from the English settlers. The third class of town, the partially fortified, was very common. The chief building and a few structures would be enclosed, leaving the remainder unprotected outside the walls. ii. THE MOUNDS The Indian earth mounds in the land of Virginia have not perished as rapidly as the wooden buildings, with the result that many mounds have survived in one fashion or another. They are of at least three kinds: the burial mound, the platform mound, and the effigy mound. But it must be admitted that to this date, as far as research has disclosed, examples of the last two categories have not yet been identified.