While few in numbers and often forgotten, around 700 United States Marines were present on D Day either ashore or as part of ships crews.
Stationed at vrious naval bases established in the U.K. Marines still had their detachment in London and the two barracks in Londonderry and Iceland, and the many ships' detachments with the Atlantic Fleet
When there was a delay in the landing schedule on Utah Beach, Rear Admiral Don P. Moon, in command of Force U, sent Marine Colonel Kerr, a member of his staff, in a patrol craft to take control and to report on how the operation was working. Kerr reported that Red Beach was clear so that waves on Green Beach, which were held up, could be diverted. This landing went so well that by the evening of D-Day most of the units had reached their objectives with surprisingly low casualties. A principal factor in this success was the heavy and accurate naval gunfire on targets inland.
Among the Marines who participated on the Omaha landings were Colonel Jeschke and Lieutenant Weldon James, who was an observer on the flagship Texas, which furnished much of the naval gunfire support.
On the eastern flank of Omaha was the British assault area. Stretching toward Caen, it was considered a key to the defense of Normandy and was the area where Germany launched its major counterattack. Two Marine officers were with the British forces in this area. Captain Herbert C. Merillat, a combat correspondent, was an observer with the Royal Marines in a landing craft, guns, large (LCG). This vessel had the mission of knocking out German pillboxes from close inshore. Colonel Bare, on board the Llangibby Castle, was attached to the British Assault Force J with the 3d Canadian Division, which went ashore near Courselles-sur-Mer. This force landed at 0810 after a naval bombardment that lasted nearly two hours, and it was able to move rapidly inland with fairly light casualties. However, once the Germans were finally convinced that this landing was not a feint for a major landing elsewhere, they launched some heavy counterattacks that prevented the Allies from seizing Caen until nearly a month later, well behind their planned schedule.
Bare, who had served in England over the past year as a staff officer with ComNavEu and COSSAC, was most impressed with British ingenuity in the preparations for Operation Overlord. He described the development of such equipment as floating docks, flexible oil pipes, floating breakwaters, artificial harbors, and a sunken ship shelter as "just unbelievable." This equipment was a salvation for the landing force, enabling it to project its strength, totally more than one and half million men, onto the Normandy beaches with sufficient power to sustain itself.
Colonels Bare and Kerr arrived back in London on the same day that the Germans launched their first V1 buzz-bomb attack on the city. They returned to Washington on the Queen Mary. Bare was transferred to the Pacific to become chief of staff of the 1st Marine Division for the invasion of Okinawa.
Extracts from;
A DIFFERENT WAR: Marines in Europe and North Africa
by Lieutenant Colonel Harry W. Edwards, U.S. Marine Corps (Ret)