Appellee makes the point that the court has no jurisdiction to determine this appeal, for that the record (loes not show that notice of appeal was 1. Notice of appeal: co-parties. served upon the defendants Owens and wife. Said defendants did- not appear or plead either to the petition of plaintiff, 'or to the cross-petition of defendant Besley. The action was tried upon the cross-petition and the answer of plaintiff thereto. The decree entered was in favor of Besley, and the effect thereof was a finding that he was entitled to reformation as against the defendants Owens, and accordingly that plaintiff was not entitled to recover as against him. The appeal was taken by plaintiff, and his complaint has sole reference to that portion of the decree which denies judgment in his favor against Besley. By section 4111 of the Code, it is provided that “a part of several co-parties may appeal; but in such case they must serve notiee of the appeal upon those not joining therein,” etc. We have held in a number of instances that a failure to serve notice of appeal upon co-parties is not jurisdictional. The court cannot, however, in such case consider any question, the *44determination of which will work prejudice to the parties upon whom notice is not served. Kellogg v. Colby, 83 Iowa, 513; Ward v. Walker, 111 Iowa, 611; Clayton v. Sievertsen, 115 Iowa, 687. In this case a reversal of the decree, as sought by appellant, could work no prejudice to the defendants Owens. On the contrary, such a result would be, to all intents and purposes, in their favor. Laprell v. Jarosh, 83 Iowa, 753, is not in conflict with the view here expressed. In effect, that. was an action • for partition-of real estate, and it was expressly .found that the interests of appellant could not be adjudicated without affecting the interests of the defendants upon whom notice of appeal had not been served. The case went off' by dismissal on motion, and there was no resistance. -We must infere, and especially in view of our other holdings referred to, that a determination of the appeal would have involved matters in some degree or to some extent antagonistic to the interests- of the defendants not made parties to the appeal, and ■ respecting which matters they were entitled to be heard. We conclude, therefore, that the point made by appellee in this case is without merit. Appellee also questions the right of appellant to prosecute the appeal upon two other minor grounds. We have-examined each thereof, and -find nothing of merit, or requiring an extended discussion at our hands.
The sole contention of appellant-is that the decree, in so far as it finds that the assumption clause in the deed to ■Besley was a mistake,-is not warranted by the record. " In 2. Reformation of deed: mistake: evidence. brief, these are the facts: Upon its face the deed recites a consideration of $1,100. Besley testifies that he traded some personal property, valued at less than $200, for the land, and that he considered the property .worth $800; that there was no agreement made that he was to pay the mortgage. He says that he did not-see the deed drawn, and that he did not read it when delivered to him by Owens, but took it *45borne and put it away; that he did not look at it or know of the provisions thereof until some two years later; and that in the meantime he had sold and conveyed the property to another. He says that he knew of the existence of the mortgage on the property, and that what he traded for was the equity. As a witness, Besley does not undertake to state any conversation between himself and Owens incident to the making of the trade, but his testimony is confined to statements of conclusions as given by us above. The defendant Owens was not called, as a witness. O. D. Wheeler, a notary, testifies that the deed was drawn by and acknowledged before him, and that the assumption clause was inserted therein by direction of Owens; that the deed, upon being executed, was delivered to Owens. There was other evidence offered and introduced, but we have set forth above all that is material to be'considered.. That Besley was bound by the provisions of the deed, and became personally liable for the amount of the mortgage debt, unless there was a mutual mistake in the draft of the deed, is well-settled doctrine. A late case to that effect is Beeson v. Green, 103 Iowa, 406. Now, to make out a case for reformation, no fraud being alleged or proven, it must be made to appear that there was a mutual' mistake, and that the contract as written does not express the agreement as actually intended by the parties. This is elementary, but see Tufts v. Larned, 27 Iowa, 330; Breja v. Pryne, 94 Iowa, 755; Williams v. Hamilton, 104 Iowa, 423. It 'is not enough to show that one of the parties made a mistake; the mistake must have been mutual. Des Moines, etc. v. Tubbessing, 87 Iowa, 138; Wachendorf v. Lancaster, 61 Iowa, 509. And the proof must be clear, full, and decisive. A mere preponderance of evidence is not enough. Tufts v. Larned, supra; Bishop on Contracts, section 708. Giving, force to the rules by which such cases are to be governed, we see no reasonable ground upo n which to sustain the decree here appealed *46from. It is altogether probable that Besley thought he was buying the property subject to the mortgage, but it is made to appear clearly that Owens thought the mortgage debt was being assumed by Besley. Such being the situation, there can be no reformation, and the provisions of the deed should be enforced as they are written. The decree is reversed, and the cause remanded for further proceedings according to law. — Revebsed.