Official Army Register, 1 January 1946, Vol. I, the "Colonels - Continued" list: Herbert S. Clarkson (I.G.D.) and Charles G. Helmick, both 1 July 1942.
Image · dated 1 January 1946 · source: U.S. War Department publication (Internet Archive scan); officialarmyregi1946unit.

How it is shown: Complete page as supplied; no crop, no retouch, no search highlight.
Keep in mind: Confirmed as printed. A federal government publication, released public although dated after 1931.