I have been researching the Benjamin Power family in Texas and I would say that Dr. Levi Brimner Salmans was almost accurate in his 1936 account of Margaret Mary (Polly) Salmans and Benjamin Power's family. He made a few mistakes but got this story thru Josiah Power's adopted daughter, Rachel, the way I understand it.
One big mistake he made was in the description of where Josiah Power was buried. I finally found his grave in the northwest part of Lavaca County and from there I was able to find more information. In Chart III, number 9 is Richard, but I'm pretty certain he went by Ira because he and his wife are on the 1860 Gonzales County, Texas Census. At that time his Mother going by the name of Mary Power was living with them. I have a Marriage Record that states Ira Power married Miss Malinda Jane Key on July 14, 1859. Her brother, John W. Key swore on a note attached to the records that his parents were willing for their daughter to marry Ira.
I have researched at the Gonzales Archives and copied the actual papers that Mary signed to be administrator of her husband, Benjamin's, and her son, Michael's estates, as both died in 1839, intestate. I have also copied the rest of the file on this family.
I have found many true stories about Comanche Indians killing in that area at that time. Although these men were only out hunting for meat to feed their family, I guess the Comanches resented their being there. Dr. Salmans says Robert Power was "killed by Mexican Indians on the Rio Grande River while freighting goods". I believe these were probably Apache Indians, but I could be wrong because his statement is all I know about it. I have read another account than Salmans' story of Josiah's capture and Levi's death by Indians in 1842, but they are very similar.
If you would like anymore information on these families, I would be interested and happy to correspond with you by e-mail. I am working on trying to confirm all the information Salmans gave on the Power Family.
By the way, my father is listed in Salmans' book on page 33 (Richard Kullin). He is the grandson of Mary Jane Power, granddaughter of Benjamin and Margaret Mary (Polly) Power.