Pershing assembled an expeditionary force consisting primarily of cavalry and horse artillery, the cavalry units armed with M1909 machine guns, M1903 Springfield rifles, and M1911 semi-automatic pistols.
Pershing immediately sent the 7th Cavalry (seven troops in two squadrons) south just after midnight on March 18 to begin the pursuit, followed by the 10th Cavalry moving by rail two days later [REF].