Sunset and The Pacific Monthly were two separate magazines that ended up combining. I found an article from 1911 that announced this (why this issue in 1914 said it was the first combined issue, I don’t know).

“Periodicals Are Combined After Long Deliberation--Northwest to Be Explotted as Usual--Lute Pease Quits Chair.” - The Sunday Oregonian, December 1911

Link to the full article: https://oregonnews.uoregon.edu/lccn/sn83045782/1911-12-03/ed-1/seq-13/