Another point I just realized- the 1850 Allegheny, Blair, PA census lists 2 Meyers families on the same page as the William McMurrays. Catharine C. McMurray, age 17, is listed with her father Wm.; the Myers fam. 6 dwellings away includes an 18 y/o William, so they were neighbors. My grandmother did tell me that a group of families came to IA from PA together, which would have been 1852.