This an interesting article from a 1952 Leatherneck magazine which reflects on the history and passion of Navy chaplains serving with the Marines:
“Faith is a mighty important word to a Marine faced with the reality of combat. Military training and confidence in his weapon and in his fellow Marines help on the physical side. But a fourth aid is just as important to many–the presence of an old friend and confidant, the Navy chaplain.
“Chaplains have been providing front line spiritual guidance and solace ever since there has been a Navy–ever since Edward Brooks received his commission as a chaplain in 1777. Since the Marine Corps has no chaplain corps of its own, its personnel have always been included within the Navy chaplains’ ministry.
“The earliest discovered reference to any extensive work by Navy chaplains directly for Marines appeared in a letter of December 4, 1862, in which Chaplain C. S. Stewart wrote to a friend describing his activities with the Marines at the New York Navy Yard Hospital.