I am at the wall with side of my family. It originated in Hungary under the name Adam. John and his wife Anna Veronica Pollock immigrated to the U.S. circa 1906. I haven't been able to track down the proper Ellis Island documents to verify the exact date.
It is my understanding that the 's' was added during the processing through the island. They originally setted in Daisytown, PA before moving to Terre Haute, Indiana after the death of John in 1921. There are numerous Pollocks around town but none of us know how we are related past the fact that my G-Grandmother Anna was a Pollock.