just did some speedy checking and this is what I came up with:
William Martin Roosa b 11 Aug 1840 Liberty-d25 May 1921 Liberty married Roxy Ann Lewis and was the father of Schuyler Roosa/Rose  born 9 June 1873 @ Liberty   also  f/o Dealia May Roosa born 18 May 1875 @ Liberty. 
other children: Elizabeth, Andrus, William, Garfield, David, Katie, and Peter.
Don't know any more about occupation than before, but he is not relative of my Roses. He was son of Jacob Delameter Roosa of Marbletown and Elizabeth E. VanBenschoten of Wawarsing. I believe they are the Roosa/Rose family that owned the Will Rose Hardware store here in the Manor and one of his brothers was Garrett Rose. Garrett is buried near my William's wives at the Manor Methodist Church Cem here in the Manor.   Hope this helps put some pieces together.
Evelyn Boyles

When I was researching my Rose's I copied a short piece out of the book the late Leslie C. Wood wrote around 1950  " Holt ! T'other Way "  (page 97 and the book can be seen at the Manor library)  about a William "Bill" Rose, also called Rosa or Roosa.  He was one of the rafters, and I was under the impression Wood meant a gggUncle of mine; however, Wood says this Bill Rose was a Livingston Manor "scrapper" who was " well over 6 feet tall and powerful  and worked as a policeman on the Ashokan Dam project at the time of the reservoir construction."    Apparently that reservoir was built earlier than I had suspected it was.   Wood was a Manor resident also, I'm not sure when he died but believe it was a few years after he wrote the book.     I had a hard time with Wood's story as I was quite certain that my William was #1 deceased, and #2 had moved to Michigan by the time the Ashokan Dam was built.  [Wood does mention my ggggrandfather John C. Rose, and my gggrandfather Fernando Rose and many of our Sprague relatives.]  So it may be your William Roosa that Wood was writing about. I notice there is a star on his belt buckle also.
Evelyn Boyles