The 100 Days Offensive, Meuse Argonne Second Phase: October 4 through October 28, 1918.

U.S. Marines, part of the U.S. 2nd Division, advancing during the Meuse Argonne Campaign.

We just read about the "Lost Battalion" yesterday. Could we really be on to a new phase?

Yes, while that drama was playing out, and would continue to, the American offensive would enter its next phase.

The second phase of the offensive began on this day.  All of the original divisions assigned the primary assault role in the first phase of the offensive were rotated out in favor of fresh divisions, the result being that the 91st, 79, 37, and 35th of the U.S. V Corps were replaced by the 32nd, 3d, and 1st Divisions.  These were not, of course, the only American divisions committed to the attack by any means, but rather the primary assault divisions.

The 1st Division, which we've read about here earlier, breached the German lines with a advance a little shorter of two miles (that being a big advance in the context of the conditions).  This gave rise in part to the Lost Battalion episode we've already read about, although as already noted the events that gave rise to that episode commenced on October 2. 

This phase of the assault was very bloody from an American prospect and it featured high American casualties.  The effort resulted in a breach of the local section of the Hindenburg line during the Battle of Montfaucon on October 14 through 17, resulting in the clearing of the Argonne Forest and an advance of ten miles. The French Army advanced even further, clearing 20 miles.

The second phase is well remembered by students of the American contribution to World War One.  The American Army was bloodied but showed itself of sustaining loss and advancing against stout German opposition. Having said that, there are real reasons to doubt that the American manner of fighting would have continued on had the Germans not ultimately collapsed in early November.  The loss rates sustained by the American Army were appalling and due, in no small part, to the troops being green and therefore willing to sustain them in a manner which the various European combatants no longer were.