members or ancestors of present members as being descendants of a historical tribe or tribes that combined and functioned as a single autonomous political entity. (B) The petitioner must provide an official membership list, separately certified by the group’s governing body, of all known current members of the group. This list must include each member’s full name (including maiden name), date of birth, and current residential address. The petitioner must also provide a copy of each available former list of members based on the group’s own defined criteria, as well as a statement describing the circumstances surrounding the preparation of the current list and, insofar as possible, the circumstances surrounding the preparation of former lists. (6) The membership of the petitioning group is composed principally of persons who are not members of any acknowledged North American Indian tribe. However, under certain conditions a petitioning group may be acknowledged even if its membership is composed principally of persons whose names have appeared on rolls of, or who have been otherwise associated with, an acknowledged Indian tribe. The conditions are that the group must establish that it has functioned throughout history until the present as a separate and autonomous Indian tribal entity, that its members do not maintain a bilateral political relationship with the acknowledged tribe, and that its members have provided written confirmation of their membership in the petitioning group. (7) Neither the petitioner nor its members are the subject of congressional legislation that has expressly terminated or forbidden the Federal relationship. 8. Previous Federal acknowledgment (a) In general Unambiguous previous Federal acknowledgment shall be acceptable evidence of the tribal character of a petitioner to the date of the last such previous acknowledgment. If a petitioner provides substantial evidence of unambiguous Federal acknowledgment, the petitioner shall only be required to demonstrate that it meets the requirements