From the Notes of "In the Hands of Providence..." (on p. 441-442) the author notes that the right flank of the 20th Maine, and the left of the 83rd Pennsylvania remained in close proximity, and kept the rebs off of Chamberlain's right flank. When unit markers were planted on the battlefield in 1869, the right of the 20th and left of the 83rd were signified by a single marker.
Today, however, on the battleground, the author notes the markers for the right of the 20th (which is slightly downhill, and according to Oates, 40 steps from the boulder in question) is 80 yards (240 feet) southeast from the left marker of the 83rd PA. Which of these flank markers is more accurately placed, and why, is unknown evidently.
Here's a view of the 83rd's left flank marker stone, with the regimental monument nearby:
The right flank marker of the 20th Maine is a short distance away.
From Oates' official report, notice that his line initially was on a ledge of rocks, the left flank at a very large rock; when it served as the pivolt for his line, wheeling left, to another ledge of rocks, perpendicular to the first ledge (on the left of which was the large rock).
So he claims his line formed on a ledge of rocks, and from a boulder to his left, as pivot, wheeled to the left to put his men on a perpendicular ledge of rocks; something like this:
Here is how Oates explained the action in his post-war book:
And this is from Chamberlain's official report:
"In order to commence by making my right firm, I formed my regiment on the right into line, giving such direction to the line as should best secure the advantage of the rough, rocky, and straglingly wooded ground.
The line faced generally toward a more conspicuous eminence southwest of ours, which is known as Sugar Loaf, or Round Top. Between this and my position intervened a smooth and thinly wooded hollow. My line formed, I immediately detached Company B, Captain Morrill commanding, to extend from my left flank across this hollow as a line of skirmishers, with directions to act as occasion might dictate, to prevent a surprise on my exposed flank and rear.
The artillery fire on our position had meanwhile been constant and heavy, but my formation was scarcely complete when the artillery was replaced by a vigorous infantry assault upon the center of our brigade to my right, but it very soon involved the right of my regiment and gradually extended along my entire front. The action was quite sharp and at close quarters. In the midst of this, an officer from my center informed me that some important movement of the enemy was going on in his front, beyond that of the line with which we were engaged. Mounting a large rock, I was able to see a considerable body of the enemy moving by the flank in rear of their line engaged, and passing from the direction of the foot of Great Round Top through the valley toward the front of my left. The close engagement not allowing any change of front,
I immediately stretched my regiment to the left, by taking intervals by the left flank, and at the same time "refusing" my left wing, so that it was nearly at right angles with my right, thus occupying about twice the extent of our ordinary front, some of the companies being brought into single rank when the nature of the ground gave sufficient strength or shelter. My officers and men understood my wishes so well that this movement was executed under fire, the right wing keeping up fire, without giving the enemy any occasion to seize or even to suspect their advantage. But we were not a moment too soon; the enemy's flanking column having gained their desired direction, burst upon my left, where they evidently had expected an unguarded flank, with great demonstration.
We opened a brisk fire at closes range, which was so sudden and effective that they soon fell back among the rocks and low trees in the valley, only to burst forth again with a shout, and rapidly advanced, firing as they came. They pushed up to within a dozen yards of us before the terrible effectiveness of our fire compelled them to break and take shelter. They renewed the assault on our whole front, and for an hour the fighting was severe.
Squads of the enemy broke through our line in several places, and the fight was literally hand to hand. The edge of the fight rolled backward and forward like a wave. The dead and wounded were now in our front and then in our rear. Forced from our position, we desperately recovered it, and pushed the enemy down to the foot of the slope. The intervals of the struggle were seized to remove our wounded (and those of the enemy also), to gather ammunition from the cartridge-boxes of disabled friend or foe on the field, and even to secure better muskets than the Enfields, which we found did not stand service well. Rude shelters were thrown up of the loose rocks that covered the ground. Captain Woodward, commanding the Eighty-third Pennsylvania Volunteers, on my right, gallantly maintaining his fight, judiciously and with hearty co-operation made his movements conform to my necessities, so that my right was at no time exposed to a flank attack."
So even Chamberlain notes his left wing swung backwards to near a right angle, giving up the ground of their original line; something like this:
but his right, aided by the 83rd PA generally held (Oates notes the right of his antagonists were fixed in place somewhere near the large rock on his left).
However, in the subsequent fighting "squads" of Confederates broke through his line in "Several" places, which he does not specify. Nor does he specify if any of these "squads" were bearing the color of the 15th Alabama... Oates says the federals counterattacked him five times. Chamberlain confirms, and admits "the edge of the fight rolled backward and forward like a wave" passing over the casualties, US and CS, in front to leave them in their rear, etc.; Theodore Gerrish of the 20th confirms this:
And Chamberlain reports the 20th was indeed "forced from our position" but that this was forcibly recovered. And of course, after a time, his regiment's final attack swept the ground of Oates' regiment.
Forum Host
Bringing the