Andrew, I'm the one who made the changes.  Mark did make some valuable changes after my mistake.  You mentioned rolling back the changes.  I have looked into this a little, but it is still confusing to me.  Are you saying that I should use the 'revert' command to roll back the changes.  This seems like it will keep the history intact, and allow me to reintroduce Mark's changes.  

Also, Is there a recommended way to remove my changes, while keeping Mark's?  With my limited understanding, I am wondering if I should revert to a commit before my changes, then copy and paste Mark's changes, and commit again.

Any help you can offer is much appreciated.  Sorry for any confusion I have caused.