delivered the Opinion of the court. This is an action of tresspass, relating 1. jan¿ in which the respective titles of the 1 parties are brought into view; their claims r ° appear to have been severe!? contested in * r fte court below, if we may judge from the . number of points made and supported, pro and r i i con an[j the many bills of exceptions which J 1 appear on the record, and on which the case is principally brought before this court. Of these exceptions we deem it necessary to examine only two, being clearly of opinion that the judge a quo, erred in rejecting the evidence, which gave rise to one of them taken by the defendants, who are here appellants. The evidence offered is a survey of part of the disputed premises, alleged to have been made. *137by and under the authority of the Spanish J ... government, as exercised in the province of Louisiana.. The plat or plan is certified by Carlos Trudeau, the surveyor general of said province, as having been executed by one- of his deputies. Since the change of government, and opening of the land-office under the authority of the United States, this plan of survey was regularly registered, and a certificate obtained from the commissioners in favor of the person claiming under it. They have, therefore, for and on the part of the United Slates, recognized it as evidence of title, and we believe in strict conformity with the act of congress, of the 3d March, 1819, cited and relied on by both parties to this suit. The legal effect which it may have in opposition to the plaintiffs’ evidence of title, will be fairly considered after its introduction. In relation to the other exception, which we think proper now to notice, i. e. to the permission given to the plaintiff to amend his petition by supplement ; we are of opinion that the judge below did not err. It does not appear to us radically to change the demand. Actual possession when legal and peaceable, is sufficient to maintain an action of tresspass. In the pre*138sent case, the supplemental petition sets forth . the manner ot possession, and title, .under wh¡cb ⅛6 plaintiffs hold, this cannot fairly he considered as a change in the substance of the demand.

It is therefore, ordered, adjudged and decreed, that the judgment of the district court be avoided, reversed and annulled; and it is further ordered and decreed, that the cause be sent back to the court below for a new trial, with instructions to the judge a quo to admit in evidence the plat or plan of survey, offered by the defendants, and that the ap-pellees pay the costs of this appeal.