This would be William Vanderlip. Like Frank, he had served in the 2nd Kansas Cavalry during the Civil War and had accompanied Frank on the 1865 Santa Fe Trail drive to Fort Union, New Mexico. In 1870 he was living just south of Frank, in Burlingame, listed on line 22. His neighbor, Sylvanus Heberling (line 34) had served in the same cavalry unit as Frank and William.