I think but am not sure he was my great-great-great grandfather (that is, the father of Emma Cosgrove Bloom, wife of Jacob E. Bloom of Ohio, USMA '73, both buried in Arlington). He commanded the regiment at Chickamauga when the LTC was killed. He is variously recorded as Horatio S. or Horatio G.
He was apparently not well liked by his brigadier:
http://www.ohiohistory.org/onlinedoc/civilwar/sa0147/35_04.cfm

If you find out more or are able to confirm he was the father of Emma, please drop me an email.