 While the coastal defenses had not turned back the invasion at the beach , they had broken up and weakened the assault formations struggling through them . The German emphasis on this Main Line of Resistance ( MLR ) meant that defenses further inland were significantly weaker , and based on small pockets of prepared positions smaller than company sized in strength . This tactic was enough to disrupt American advances inland , making it difficult even to reach the assembly areas , let alone achieve their D @-@ Day objectives . As an example of the effectiveness of German defenses despite weakness in numbers , the 5th Ranger battalion was halted in its advance inland by a single machine gun position hidden in a hedgerow . One platoon attempted to outflank the position , only to run into another machine gun position to the left of the first . A second platoon dispatched to take this new position ran into a third , and attempts to deal with this met with fire from a fourth position . The success of the MLR in blocking the movement of heavy weapons off the beach meant that , after four hours , the Rangers were forced to give up on attempts to move them any further inland . 
