With small variations in details, the general construction outlined above was employed by many North American Indians for building temporary canoes for emergency use. In at least one case, however, it was also used in canoes of somewhat more permanent status within the boundaries of the powerful Iroquois Confederation. On large bodies of water within their territory, the Iroquois used dugouts, but for navigating streams and for use in raiding their enemies they employed bark canoes. While some birch bark was available there, it was probably widely scattered; therefore these great warriors used elm or other bark for their canoe building. Early French accounts show that the Iroquois built bark canoes of greater size than ordinary; Champlain wrote that their canoes were of oak bark and were large enough to carry up to 18 warriors; later French accounts, as we shall see, indicate that the Iroquois used even larger canoes than these. Champlain may have been in error about the Iroquois use of oak bark, as suggested earlier (p. 7), for experiments have shown that the inner bark of this tree is too thin and weak for the purpose; the canoes Champlain saw may have been built of white or red elm bark. The barks of the butternut, hickory, white pine, and chestnut might also have been employed, as they were usually suitable. It was noted by the early French writers that the Iroquois built their bark canoes very rapidly when these craft were required by a war party in order to attack their enemies or to escape pursuit. In one case at least the canoes for a war party were apparently built in a single day. This was accomplished, it seems, by the excellent organization of their war parties, in which every man was assigned a duty, even in making canoes.