delivered the opinion of the Court. On a former hearing of this case on demurrer to the bill, founded on a supposed want of jurisdiction in the Court or power to decae specific execution of the award, the demurrer was overruled, and the defendants were ordered to make answer to the bill. [See 4 Pick. 507.] An answer having been filed, to which there have been no exceptions, the case has been argued upon the general question, whether any thing contained in the answer is sufficient to show that the award is bad in law, or whether on any grounds of equity the defendants ought to be relieved from its effects.

It has been urged, that the award is bad in itself, in not being mutual, that is, in not providing that a release should be given by the plaintiff to the defendants, of land supposed to be contained in the description of land claimed by the plaintiff, but not confirmed to him by the award ; a release being required from the defendants of all the residue of the land within his claim. We do not find it essential to the validity of an award, that releases should be required on both sides, if the title is so ascertained by the award itself, as to leave no room for disputation. By the submission, authority was given to the arbitrators to require such deeds of release as should be neces • sary and proper to give effect to the award. The arbitrators awarded a release from the defendants to the plaintiff, of the land which they determined the plaintiff ought to hold, and this was proper, as the defendants were in possession claiming title ; and though, without a release, the award would have been conclusive between the parties as to the extent of their *154several claims, it was more convenient that the claims and possession of the defendants should be extinguished by a deed of release, which of course, when duly executed and delivered, would admit of no dispute. Perhaps it would have been better to require a release from the plaintiff to the defendants, of all lands without the bounds ascertained by the award; but as the defendants were already in possession, claiming the land under their general title as proprietors of the mill pond, a release was by no means essential to them. The award itself settles the limits of the plaintiff’s claim, and there was no possession or claim of right on his part beyond the boundary established by the award ; so that there is no want of mutuality in any thing in the least degree important to the parties. And it may be added, that if a release from the plaintiff to the defendants were necessary, to carry into effect the award, as he has covenanted to make and execute any deed of release which may be necessary for that purpose, he might be compelled by a bill to perform that covenant. But a release was not necessary to either party, for it is clear that the award itself would establish the title.1 In Shepherd v. Ryers, 15 Johns. R. 497, it was held, that an award of land to one party estops the other from setting up title to the land awarded ; and in Sellick et al. v. Addams, p. 197 of same volume, it was held, that when an award settles the boundary of land, the party to whom it is awarded may maintain ejectment, or justify in trespass brought by the other party.

Another objection to the award is, that the arbitrators proceeded upon a mistaken construction of the right of the plaintiff to flats as appurtenant to his upland under the colonial ordinance of 1641, and that for this cause the defendants ought to be relieved from a specific execution.

It is answered, on the part of the plaintiff, that an award will not he set aside, or its execution superseded, on account *155of any supposed mistake of the arbitrators in matter of law, unless it appears by the award itself that it is defective in the point suggested.

There seems to be considerable contrariety of opinion in courts of law and equity upon this subject, and it is not easy to reconcile the opinions and reasonings of different judges thereon.

It was formerly held, that awards should not be set aside on account of any erroneous opinion in matter of law, unless the error appeared on the face of the award. But in Kent v. Elstob, 3 East, 18, there is a decision which greatly relaxes this rule. The arbitrator stated his reasons and delivered them on a separate paper to the parties. It was obvious that he meant to decide according to law, and was mistaken. The award was set aside on a rule, because the law was mistaken. Laivrence J. says it is not necessary that the arbitrator’s reasons should appear on the face of the award, in order to enable the court to examine them. The reasons appearing on a separate paper were considered to be before the court, as much as if they had appeared on the award itself.

But in the case of Chase v. Westmore, 13 East, 357, very different ground is taken by Lord Ellenborough. The case, involving a question of law, was referred to a gentleman of the bar. There was a motion to set aside the award because he mistook the law. The question of law was raised in the pleadings, but did not appear on the face of the award, though it was brought before the court by affidavit. The chief justice said he “ feared it was impossible to lay down any general and certain rule. It is enough to say, that in the present case, where the merits in law and in fact were referred to a person competent to decide upon both, we will not open the award, unless it could be shown to be so notoriously against justice and his duty as an arbitrator, that we could infer misconduct on his part.” The other justices agreed, and Le Blanc J. said, when the question of law necessarily arises on the face of the award, then the court must take notice of it.

Now these two cases in the same court are quite contradictory, so that it will not be safe to take either of them for a guide.

*156By the decisions in chancery, it would seem to be considered as discretionary to set aside an award or not, on matter of law, according to what shall be deemed to be on the whole the justice of the case. Thus, if the arbitrators appear to be mistaken in a doubtful matter of law, the award may be permitted to stand, though the court after great deliberation should be of a different opinion from the arbitrator. Kyd on Awards, 351.

But the general rule in chancery seems to be, that awards may be set aside for matter in law, and it does not appear that it is necessary the error should appear on the award itself; at least that is not stated to be requisite.

Thus in a note to the case in 14 Ves. 271, it is stated, that under a general reference, the mistake of the arbitrator, meaning to decide according to law, will be corrected ; but if parties refer a question of law to an arbitrator, meaning to have his decision, the court will not interfere. So in 9 Ves. 364. If they refer to a person to decide all matters in difference according to law, and the arbitrator means to decide according to law, and mistakes, the court will set this right. But if a distinct question of law, and nothing else, is referred, and the parties choose to say they will not take the decision of the court, but will take whatever an arbitrator shall say is the law, why may they not so agree ?

It is pretty clear then, that there is no definite rule on the subject in the English books, and yet there ought to be, and must be, some principle by which questions of this kind are to be settled. We take one principle to be very clear, which is, that where it manifestly appears by the submission, that the parties intended to leave the whole matter, law and fact, to the decision of arbitrators or referees, the award is conclusive, although they should have' mistaken the law, unless the award itself refers such question to the consideration of the Court. And this is enough to settle the case. before us ; for by the agreement to submit to arbitrators, all matters of law are expressly referred to the arbitrators in these words : — “It is agreed that the parties hereto may introduce any legal evidence in support of their respective rights and claims, and that the legal construction thereof is submitted to said referees.” It is *157not objected that any evidence not legal was admitted, and that is the only limitation to the authority of the arbitrators. They have given their construction upon all the evidence, and the parties cannot retract their agreement upon the allegation of a mistake. They selected a tribunal in all respects competent to decide a complicated case of law and facts; and if their opinion on the matter in law should not be adopted by the court, their judgment is nevertheless to stand. The law on the point on which it is said they were mistaken, was, to say the least, very doubtful; and upon that ground the award ought to stand, according to the doctrine cited from Kyd; and their opinion is so far from being notoriously wrong, that it is highly probable one half of the profession would have given the same opinion, and so, according to Lord Ellenborough, in the case in 13 East, this forms no ground for setting aside the award.1

Another ground for resisting the decree, as set forth in the answer, is the alleged surprise of the defendants and their counsel, as to the importance attached to one of the subjects of discussion, so that they were not prepared to argue it as a principal matter in dispute. But we cannot listen to this complaint. A full and patient hearing was given ; the point referred to was raised and urged by the defendants’ counsel; if they were surprised, they should have applied for time. There was nothing urged which was beyond the subject matter of the arbitration. The claim of the plaintiff, as heard and decided upon by the referees, was according to his description in the submission ; for it extended over to the causeway. The defendants should not have been surprised at the attempt to enforce this claim to its extent; and there is no extrinsic evidence from which we can perceive any intention to diminish his claim.

Specific performance decreed.2