According to Shelby L. Stanton's "WW III Order of Battle" the 46th A/I BN was a part of the Fifth Armored Division, which was attached to XV Corps from 1 Aug 44. The division was under command of Major General Lnford E. Oliver from MAR-43.
Following other operations, the division crossed the Mayene River, and captured Le Mans, 8 Aug 44.
On 9 Aug 44, it swung north toward Alencon, and advanced to the edge of Argenten, which it left to the 90th Infantry Division.
It advanced 60 miles to reach the Eure River at Dreux, which fell 16 Aug 44.
I speculate that the division would have been within 20 miles of Dreux when he fell.