As an addition to my answer, I wondered how BG Rice got the nickname "Old Crazy". I found the answer in the book, "In The Hands of Providence: Joshua L. Chamberlain and The American Civil War", page 150: An order to capture Round Top for the Union soon came from the Corps commander. It was dusk and Colonel Rice, whose excitement in battle had earned him the affectionate nickname of "Old Crazy"by his men, asked Colonel Joseph W. Fisher to take his Pennsylvania Reserves up to the darkening slope of Great Round Top and seize it". I Love a Mystery !
I was interested to find that Rice is portrayed in the movie “Gettysburg.” He is the New York commander who comes down the hill to congratulate Joshua Chamberlain for repelling the Confederate assault on the Union left flank at Little Round Top.