Which formation is NOT considered a type of infantry formation?

The formation identified as a circle is not considered a type of infantry formation primarily because infantry formations are designed to maximize combat effectiveness, maneuverability, and command and control on the battlefield. A circle formation lacks a distinct front or rear, which can hinder the unit's ability to engage the enemy effectively and to utilize supportive elements like fire support or artillery. In contrast, the other formations—wedge, column, and echelon—are all structured with clear advantages for tactical purposes, allowing for easier movement, communication, and engagement with enemy forces.

The wedge formation allows for a strong front with the capability to create firepower toward the enemy while providing protection against flanking attacks. The column formation facilitates movement over longer distances and is useful in constrained environments, while the echelon formation allows for a layered approach, enabling units to focus firepower on a specific direction while maintaining depth in their defense. Each of these formations serves distinct tactical functions that align with infantry operations, showcasing the reason why the circle formation does not fit the same criteria.