Pennsylvania Statutes Title 64 P.S. Public Lands § 387. All surveys previously returned, and accepted, declared valid

All the surveys of land heretofore returned and accepted by the officers of the land office,  1 are hereby declared to be valid and effectual, to all intents and purposes, notwithstanding the said surveys may have been actually made on the ground before the warrants on which they were returned had been placed in the hands of the deputy surveyor:  2 Provided, That this act shall not be so construed as to alter or impair the existing rights of third persons.