Oh I know, I about flipped when I saw the title and date stamp!
As far as I know, this is the earliest known surviving page. The artwork for the text story in Detective #11 is out there, but that book is cover dated Jan 1938 & appears to have hit the newsstands 12/30/37. The Star Ranger #2 is cover dated April 1937 and was apparently on the stands 3/10/37. The Detective #11 is signed "Creig Flessel Algiers 1937", but no specific date is noted. Being on the stands 9 months prior to the Detective, I'd guess that the Star Ranger was done quite a bit in advance of the Detective art. I'd love to own that Detective piece!!!