What is your source for Boone joining Shannon's company? A pension record? Is it possible to get a copy of it? As Ken Martin said, it would not be unlikely, although rare, to find a Texan in the ranks of the Cherokee regiments. There were a substantial number - up to 25% - of non-Cherokees (i.e. white men who were not citizens of the Cherokee Nation) who served in these units, although most of these men were from NW Arkansas. While joining an Indian unit would constitute a breach of the conscription regulations as they applied to Texas residents, it was not illegal for whites to serve in Indian units. Also, by 1864 the manpower shortage in the Confederate army was acute, and unit commanders were not likely to be too particular about signing people up.