The 1913 PCL pass has a note signed by the club owner, W.W. McCredie, in the upper right. The 1918 pass is notable because Portland was booted from the PCL that year and played in the Pacific Coast International League (unlike the 1913 pass, the signature on the 1918 pass is secretarial). More early Portland material is within the first 15 galleries at
http://www.sportingoregon.com/f586168153 . Open a gallery, click show all at the bottom, and click on an image for a closer look and description. For more like the two Philadelphia postcards of Ed Plank and Claude Derrick, see the other galleries on that page, especially the Unusual Postcards gallery.