Corry342:  Nice detail on the Electric Flag.  From my knowledge of the group, my guess is that Goldberg quit the group due to the excessive drug use.  Bloomfield played with him a bit later, but his main collaborator after the 1960's on keyboards was Mark Naftalin (a better piano player than Goldberg anyway; the latter was better on organ).  They teamed up through the 1970's, as I guess Naftalin could deal with Bloomfield's undependability.  

I am repeating myself here, but if we can get Bloomfield on VIDEO with Butterfield or the Flag, watch for this.  He was so into it that it's scary.  Put some speed in him, get him playing the blues, and bingo....  Later his drug of choice was heroin, but early Bloomfield was an upper kind of guy.  Watch him in Monterey Pop, although that could have been acid instead.