The opinion of the court was delivered,
by Agnew, J.Owing to the legislation in this state in relation to fences, it has been held that an owner of improved land, who leaves it without a fence, cannot recover for the inadvertent trespass of a neighbor’s cattle: ■ Gregg v. Gregg, 5 P. F. Smith 227. But this rule, which flows solely from the breach of a statute duty, is not applicable to a case like this, where the duty to fence was not only common to both parties, but was waived by mutual consent. This is the case of adjoining improved lands governed by the Act of 11th March 1842, Pamph. L. 62, where each owner, if he would escape the burthen of fencing his whole land within his line, must pay for the one-half of the cost of a partition-fence, the expense of which is to be assessed by the township auditors. The keeping up of the partition-fence being a common duty, it was in the power of both to waive it; and they would clearly be liable to each other for trespasses upon each other’s fields. After an agreement not to fence between themselves, it does not lie in the mouth of either party to set up the statute duty to fence under the Act of 1700 as a bar to a recovery for the trespasses of his cattle. Having *237waived the duty on part of his neighbor in consideration of his neighbor’s waiver of his duty, he is estopped from denying his own duty of keeping up his cattle. Gregg v. Gregg was not a case between the owners of adjoining improved lands, and is therefore no authority for this case.
The judgment must therefore be affirmed.