46 F.3d 1122
NOTICE: Fourth Circuit I.O.P. 36.6 states that citation of unpublished dispositions is disfavored except for establishing res judicata, estoppel, or the law of the case and requires service of copies of cited unpublished dispositions of the Fourth Circuit.Willie Joe CHRISTOPHER, Plaintiff-Appellant,v.JAIL OFFICERS OF STAFFORD COUNTY JAIL;  Billy Joe Chambers;Allen Griggs, Defendants-Appellees,andStafford County Jail, Defendant.
No. 94-6870.
United States Court of Appeals, Fourth Circuit.
Submitted Nov. 22, 1994.Decided Jan. 18, 1995.

Willie Joe Christopher, Appellant Pro Se.  Jack L. Gould, Fairfax, VA, for Appellees.
Before WILKINS, NIEMEYER, and MICHAEL, Circuit Judges.
OPINION
PER CURIAM:


1
Appellant Christopher appeals from the magistrate judge's order dismissing his 42 U.S.C. Sec. 1983 (1988) action for failure to obey the magistrate judge's order and failure to participate in discovery.  This case was before the magistrate judge on the consent of the original parties to the action pursuant to 28 U.S.C.A. Sec. 636(c) (West 1993).  When, however, defendant Griggs was made an additional party to this case, consent to hear this case before the magistrate judge was never obtained from him.  Because defendant Griggs never consented to the jurisdiction of the magistrate judge, dispositive matters decided by the magistrate judge must be referred by the magistrate judge to the district court for approval by the court.


2
Consent is "the linchpin of the constitutionality of 28 U.S.C. Sec. 636(c)."  Adams v. Heckler, 794 F.2d 303, 307 (7th Cir.1986), and consent must be clearly and unambiguously stated.  It cannot be inferred from the parties' conduct.  Hall v. Sharpe, 812 F.2d 644, 646-47 (11th Cir.1987).  Absent consent, we are without jurisdiction to entertain Christopher's appeal directly from a magistrate judge's order.  See Gomez v. United States, 490 U.S. 858, 870 (1989);  Lovelace v. Dall, 820 F.2d 223, 225 (7th Cir.1987).  We dispense with oral argument because the facts and legal contentions are adequately presented in the materials before the Court and argument would not aid the decisional process.


3
DISMISSED.

