I'm just finding this on Ancestry. That's the right David Spurgin who was married to Mary Ellen Gallaher. They are buried at St. Paul Cemetery. I've been in touch with one of their descendants, Jason Spurgin, who still lives in the area.
I keep trying to find some sort of proof that the Gallahers and Gallaghers were related. So far the most conclusive evidence I have of this is that on the 1870 Collin Co. census the Gallagher's aunt Ellen Gallagher was living in 1870 with my gg-gf William Gallaher and his family. They all lived in the St. Paul/Winningkoff area. On all the other censuses Aunt Ellen was living with some of her Gallagher family. Why would she be living with William Gallaher if he wasn't family. By their ages, I think he had to be a brother. He came to the US several years before the Gallaghers. He was in the Sherman area in the early 1850's, then lived a few years across the state line in Indian Territory before coming to Winningkoff, Collin Co., TX in the late 1850's.
IF you know anything on this, I'd love to hear!