32 Pa. Stat. § 556
No incorporated boom company upon said streams shall be held legally responsible for any logs or lumber, such as they are authorized by their respective charters to catch or stop, that may escape from any booms, unless the same shall have been duly marked as aforesaid, with registered marks, and the production to the officers of said companies of a certificate, as provided in the second section of this act, shall be sufficient evidence to warrant the delivery of any lumber caught in said booms, to the person, party or company certified to be the owner or owners of the marks thereon, or his, her or their agent or agents, in the absence of any express notice of any other claim to the same: Provided, That this section shall not be so construed as to prevent the said companies from collecting boomage upon such nonmarked lumber, according to the provisions of their respective charters: Provided further, That such boom companies shall not be released from legal responsibility for any such logs or lumber as may escape from the control of the owner or owners, by reason of high water, or from other causes, which may be stopped by, or come into any boom, as aforesaid.
32 P.S. § 556