Is the full text of the "Union Indian Brigade" contained in the two volume "Civil War on the Western Border"? I found some passages are identical but haven't compared close enough to know if there is additional text in the Union Indian Brigade.

IMHO, Britton is excellent, biased but not deceptive, and perhaps less biased than most authors then and now. I think he "called it like he saw it" from his personal subjective point of view.