Thanks for your responses, everyone. I didn't realize that battalion was synonymous with regiment in this case.
I recently finished reading Hess' Civil War Infantry Tactics, in order to get answers to these kinds of questions.
My understanding is that the words, battalion and regiment were often used interchangeably. Under that assumption, a brigade that is in "column by battalion," would look like the following:
Thanks for the diagram. That Hess book has been on my Amazon list since it came out for the same reason you mentioned. I've just been waiting for the price to go down. How is the book as a whole?
This is a good picture of a regiment in column but I believe in the instance in the op it would be hard to conceal such a formation where you probably could in a narrow ravine in a 4 wide formation. Would be interesting to see a map where that took place, would probably shed light on it.
The action described took place east of the base of South Mountain at Crampton's Gap. Colonel Bartlett was ordered to move his brigade and approach the mountain with as much secrecy as possible. He found a ravine behind which he could conceal the troops from the artillery on Gapland Road and Brownsville Pass.
Based on the terrain there, my guess is that the ravine was less likely the narrow, deep gorge I usually associate with that word and instead more like a mini-valley between the rolling hills at the base of the mountain. There are a few streams in the immediate area, but they are very small and not wide at all (at least not today they aren't).
My motivation for asking this question was to try to figure out where he could have moved the troops, so I wanted to know approximately how wide his column would have been. Next time I visit there I'll be better able to picture the formation and hopefully identify the route they might have taken in their approach.
In the map below, look for SLOCUM's division and the arrow marked "3 p.m.". I believe that is the movement being described in the OR I quoted above.
[Image by Gene Thorp from Ezra Carman Vol. 1 - South Mountain, edited by Tom Clemens.]