A quick search in the Philadelphia Marriage Index online shows that Katherine married Albert Fairhurst in 1908. Their marriage license is # 232358.

If you have not already, you should pull the marriage license as it may have information on parentage for both parties.
If you are not local, someone may pull it for you at the Phila. Archives, otherwise you need to write to the Register of Wills in Phila. They do not send "informational" copies, just certified and exemplified copies. The latter is more expensive and necessary for apostille purposes.