The insignia of the 3d Marine Division was adopted on 25 August 1943, when the division was in training on Guadalcanal for the upcoming invasion of Bougainville. Approved in 3d Marine Division Memorandum 274-43, the insignia consisted of a caltrop on a triangular, gold-bordered scarlet shield. The caltrop was a medieval defensive weapon used against both cavalry and infantry. During the warfare of the Middle Ages, large numbers of caltrops were scattered by defenders on the ground in front of an approaching enemy. The four-pronged, forged-iron caltrop was designed so that no matter which way it landed when thrown on the ground, one point would be up with the other three points supporting it. When used on the insignia, the caltrop represented not only the 3d Marine Division, but also the motto painted on the drums carried by the Continental Marines in the American Revolution: “Don’t Tread on Me.”
The Southern Beaches
In the south at Agat, despite favorable terrain for the attack, the 1st Brigade found enemy resistance at the beachhead to be more intense than that which the 3d Division found on the northern beaches. Small arms and machine gun fire, and the incessant fires of two 75mm guns and a 37mm gun from a concrete blockhouse with a four-foot thick roof built into the nose of Gaan Point, greeted the invading Marines as the LVTs churned ashore. The structure had been well camouflaged and not spotted by photo interpreters before the landing nor, unfortunately, selected as a target for bombing. As a result, its guns knocked out two dozen amtracs carrying elements of the 22d Marines. For the assault forces’ first hours ashore on W-Day on the southern beaches, the Gaan position posed a major problem.
FRONTLINE—W-DAY
ASAN BEACHHEAD
Only Approximate Form Lines Shown
The assault at Agat was treated to the same thunderous naval gunfire support which had disrupted and shook the ground in advance of the landings on the northern beaches at Asan. When the 1st Brigade assault wave was 1,000 yards from the beach, hundreds of 4.5-inch rockets from LCI(G)s (Landing Craft, Infantry, Gunboat) slammed into the strand. It would be the last of the powerful support the troops of the brigade in assault would get before they touched down on Guam.
While the LVTs, the DUKWs (amphibious trucks), and the LCVPs were considerably off shore, there was virtually no enemy fire from the beach. An artillery observation plane reported no observed enemy fire. The defenders at Agat, however, 1st and 2d Battalions, 38th Infantry, would respond in their own time. The loss of so many amtracs as the assault waves neared the beaches meant that, later in the day, there would not be enough LVTs for the transfer of all supplies and men from boats to amtracs at the Agat reef. This shortage of tractors would plague the brigade until well after W-Day.