If you check the WW II GenForum and enter 1174, you will pick up on my response to Todd Walker dated 7-4-00, which provides the information you desire.
As for the division's mission, it was the liberation of Europe.
His division entered combat 11 July 44, and was enroute to St. Lo, Franceon 14 July 44, and captured it 18 July 44. Which suggests that he died on the drive on St. Lo from the town of St. Gilles, France.
The division had 264 days in combat, experiencing a total of 25,488 casualties, or 180.9%.
I am sorry that Elmer was one of 2,485 lost by the 35th. ID.