"For most conspicuous bravery, determination and leadership in the attack on the Sambre-Oise canal, near Catillon on the 4th November 1918, when a partly constructed bridge came under concentrated fire and was broken before the advanced troops of his Battalion could cross.
Lt-Col Marshall at once went forward and organised parties to repair the bridge. The first party was soon killed or wounded, but by personal example he inspired and volunteers were instantly forthcoming.
Under intense fire and with complete disregard of his own safety, he stood on the bank encouraging his men and assisting in the work, and when the bridge was repaired, attempted to rush across at the head of his Battalion and was killed doing so.
The passage of the canal was of vital importance, and the gallantry displayed by all ranks was largely due to the inspiring example set by Lt-Col Marshall."
The London Gazette - 13th February 1919.