Section 4.24 - Basis of decision(a)Record.(1) The record of a hearing shall consist of the transcript of testimony or summary of testimony and exhibits together with all documents and requests filed in the hearing.(2) If a hearing has been held on an appeal pursuant to instructions of an Appeals Board, this record shall be the sole basis for decision insofar as the referred issues of fact are involved except to the extent that official notice may be taken of a fact as provided in paragraph (b) of this section.(3) Where a hearing has been held in other proceedings, the record made shall be the sole basis for decision except to the extent that official notice may be taken of a fact as provided in paragraph (b) of this section.(4) In any case, no decision after a hearing or on appeal shall be based upon any record, statement, file, or similar document which is not open to inspection by the parties to the hearing or appeal, except for documents or other evidence received or reviewed pursuant to § 4.31(d) .(b)Official notice. Official notice may be taken of the public records of the Department of the Interior and of any matter of which the courts may take judicial notice.36 FR 7186, Apr. 15, 1971, as amended at 53 FR 49660, Dec. 9, 1988; 88 FR 5792 , Jan. 30, 2023